Vulnerability-Lookup

BDU:2026-14268

Vulnerability from fstec - Published: 21.06.2026

Title

Уязвимость функции p9_client_walk() модуля net/9p/client.c реализации протокола 9P ядра операционной системы Linux, позволяющая нарушителю оказать воздействие на конфиденциальность, целостность и доступность защищаемой информации

Description

Уязвимость функции p9_client_walk() модуля net/9p/client.c реализации протокола 9P ядра операционной системы Linux связана с разыменованием указателя с истекшим сроком действия. Эксплуатация уязвимости может позволить нарушителю, действующему удалённо, оказать воздействие на конфиденциальность, целостность и доступность защищаемой информации

Severity


                    
                      AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Vendor

Сообщество свободного программного обеспечения, Canonical Ltd.

Software Name

Debian GNU/Linux, Ubuntu, Linux

Software Version

11 (Debian GNU/Linux), 12 (Debian GNU/Linux), 22.04 LTS (Ubuntu), 24.04 LTS (Ubuntu), 13 (Debian GNU/Linux), 26.04 LTS (Ubuntu), от 6.2 до 6.6.143 включительно (Linux), от 6.7 до 6.12.94 включительно (Linux), от 6.13 до 6.18.37 включительно (Linux), от 6.19 до 7.1.2 включительно (Linux), от 6.0 до 6.1.176 включительно (Linux)

Possible Mitigations

В условиях отсутствия обновлений безопасности от производителя рекомендуется придерживаться "Рекомендаций по безопасной настройке операционных систем LINUX", изложенных в методическом документе ФСТЭК России, утверждённом 25 декабря 2022 года. Использование рекомендаций: Для Linux: https://git.kernel.org/linus/1a3860d46e3eb47dbd60339783cdad7904486b9f https://git.kernel.org/stable/c/99c379ca1e221c3d75c7c804ebbf4e5ee37a3070 https://git.kernel.org/stable/c/b84f46179c806450b89821221ea5bd9a1698aba8 https://git.kernel.org/stable/c/a61bdcba4f64c2f90d01461913f429ab151f1ca6 https://git.kernel.org/stable/c/6dbe9443d9f5f7fb6d319a7b77108853ae6c6bea https://git.kernel.org/stable/c/a7656d368265d085ac9bb85ab31b0cdb72ad8c38 Для Debian GNU/Linux: https://security-tracker.debian.org/tracker/CVE-2026-63795 Для Ubuntu: https://ubuntu.com/security/CVE-2026-63795

Reference

https://www.cve.org/CVERecord?id=CVE-2026-63795 https://git.kernel.org/linus/1a3860d46e3eb47dbd60339783cdad7904486b9f https://git.kernel.org/stable/c/99c379ca1e221c3d75c7c804ebbf4e5ee37a3070 https://git.kernel.org/stable/c/b84f46179c806450b89821221ea5bd9a1698aba8 https://git.kernel.org/stable/c/a61bdcba4f64c2f90d01461913f429ab151f1ca6 https://git.kernel.org/stable/c/6dbe9443d9f5f7fb6d319a7b77108853ae6c6bea https://git.kernel.org/stable/c/a7656d368265d085ac9bb85ab31b0cdb72ad8c38 https://security-tracker.debian.org/tracker/CVE-2026-63795 https://ubuntu.com/security/CVE-2026-63795

CWE

CWE-416, CWE-825

JSON

To clipboard

{
  "CVSS 2.0": "AV:N/AC:L/Au:N/C:C/I:C/A:C",
  "CVSS 3.0": "AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
  "CVSS 4.0": null,
  "remediation_\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": null,
  "remediation_\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435": null,
  "\u0412\u0435\u043d\u0434\u043e\u0440 \u041f\u041e": "\u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f, Canonical Ltd.",
  "\u0412\u0435\u0440\u0441\u0438\u044f \u041f\u041e": "11 (Debian GNU/Linux), 12 (Debian GNU/Linux), 22.04 LTS (Ubuntu), 24.04 LTS (Ubuntu), 13 (Debian GNU/Linux), 26.04 LTS (Ubuntu), \u043e\u0442 6.2 \u0434\u043e 6.6.143 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e (Linux), \u043e\u0442 6.7 \u0434\u043e 6.12.94 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e (Linux), \u043e\u0442 6.13 \u0434\u043e 6.18.37 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e (Linux), \u043e\u0442 6.19 \u0434\u043e 7.1.2 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e (Linux), \u043e\u0442 6.0 \u0434\u043e 6.1.176 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e (Linux)",
  "\u0412\u043e\u0437\u043c\u043e\u0436\u043d\u044b\u0435 \u043c\u0435\u0440\u044b \u043f\u043e \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044e": "\u0412 \u0443\u0441\u043b\u043e\u0432\u0438\u044f\u0445 \u043e\u0442\u0441\u0443\u0442\u0441\u0442\u0432\u0438\u044f \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0439 \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u043e\u0442 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u044f \u0440\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0443\u0435\u0442\u0441\u044f \u043f\u0440\u0438\u0434\u0435\u0440\u0436\u0438\u0432\u0430\u0442\u044c\u0441\u044f \"\u0420\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0430\u0446\u0438\u0439 \u043f\u043e \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0439 \u043d\u0430\u0441\u0442\u0440\u043e\u0439\u043a\u0435 \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u044b\u0445 \u0441\u0438\u0441\u0442\u0435\u043c LINUX\", \u0438\u0437\u043b\u043e\u0436\u0435\u043d\u043d\u044b\u0445 \u0432 \u043c\u0435\u0442\u043e\u0434\u0438\u0447\u0435\u0441\u043a\u043e\u043c \u0434\u043e\u043a\u0443\u043c\u0435\u043d\u0442\u0435 \u0424\u0421\u0422\u042d\u041a \u0420\u043e\u0441\u0441\u0438\u0438, \u0443\u0442\u0432\u0435\u0440\u0436\u0434\u0451\u043d\u043d\u043e\u043c 25 \u0434\u0435\u043a\u0430\u0431\u0440\u044f 2022 \u0433\u043e\u0434\u0430.\n\n\u0418\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 \u0440\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0430\u0446\u0438\u0439:\n\u0414\u043b\u044f Linux:\nhttps://git.kernel.org/linus/1a3860d46e3eb47dbd60339783cdad7904486b9f\nhttps://git.kernel.org/stable/c/99c379ca1e221c3d75c7c804ebbf4e5ee37a3070\nhttps://git.kernel.org/stable/c/b84f46179c806450b89821221ea5bd9a1698aba8\nhttps://git.kernel.org/stable/c/a61bdcba4f64c2f90d01461913f429ab151f1ca6\nhttps://git.kernel.org/stable/c/6dbe9443d9f5f7fb6d319a7b77108853ae6c6bea\nhttps://git.kernel.org/stable/c/a7656d368265d085ac9bb85ab31b0cdb72ad8c38\n\n\u0414\u043b\u044f Debian GNU/Linux:\nhttps://security-tracker.debian.org/tracker/CVE-2026-63795\n\n\u0414\u043b\u044f Ubuntu:\nhttps://ubuntu.com/security/CVE-2026-63795",
  "\u0414\u0430\u0442\u0430 \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0438\u044f": "21.06.2026",
  "\u0414\u0430\u0442\u0430 \u043f\u043e\u0441\u043b\u0435\u0434\u043d\u0435\u0433\u043e \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f": "09.09.2026",
  "\u0414\u0430\u0442\u0430 \u043f\u0443\u0431\u043b\u0438\u043a\u0430\u0446\u0438\u0438": "09.09.2026",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": "BDU:2026-14268",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440\u044b \u0434\u0440\u0443\u0433\u0438\u0445 \u0441\u0438\u0441\u0442\u0435\u043c \u043e\u043f\u0438\u0441\u0430\u043d\u0438\u0439 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "CVE-2026-63795",
  "\u0418\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f \u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0430",
  "\u041a\u043b\u0430\u0441\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043a\u043e\u0434\u0430",
  "\u041d\u0430\u0437\u0432\u0430\u043d\u0438\u0435 \u041f\u041e": "Debian GNU/Linux, Ubuntu, Linux",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u041e\u0421 \u0438 \u0442\u0438\u043f \u0430\u043f\u043f\u0430\u0440\u0430\u0442\u043d\u043e\u0439 \u043f\u043b\u0430\u0442\u0444\u043e\u0440\u043c\u044b": "\u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Debian GNU/Linux 11 , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Debian GNU/Linux 12 , Canonical Ltd. Ubuntu 22.04 LTS , Canonical Ltd. Ubuntu 24.04 LTS , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Debian GNU/Linux 13 , Canonical Ltd. Ubuntu 26.04 LTS , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u043e\u0442 6.2 \u0434\u043e 6.6.143 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u043e\u0442 6.7 \u0434\u043e 6.12.94 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u043e\u0442 6.13 \u0434\u043e 6.18.37 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u043e\u0442 6.19 \u0434\u043e 7.1.2 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u043e\u0442 6.0 \u0434\u043e 6.1.176 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e ",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0444\u0443\u043d\u043a\u0446\u0438\u0438 p9_client_walk() \u043c\u043e\u0434\u0443\u043b\u044f net/9p/client.c \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0430 9P \u044f\u0434\u0440\u0430 \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u043e\u0439 \u0441\u0438\u0441\u0442\u0435\u043c\u044b Linux, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u043e\u043a\u0430\u0437\u0430\u0442\u044c \u0432\u043e\u0437\u0434\u0435\u0439\u0441\u0442\u0432\u0438\u0435 \u043d\u0430 \u043a\u043e\u043d\u0444\u0438\u0434\u0435\u043d\u0446\u0438\u0430\u043b\u044c\u043d\u043e\u0441\u0442\u044c, \u0446\u0435\u043b\u043e\u0441\u0442\u043d\u043e\u0441\u0442\u044c \u0438 \u0434\u043e\u0441\u0442\u0443\u043f\u043d\u043e\u0441\u0442\u044c \u0437\u0430\u0449\u0438\u0449\u0430\u0435\u043c\u043e\u0439 \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u0438",
  "\u041d\u0430\u043b\u0438\u0447\u0438\u0435 \u044d\u043a\u0441\u043f\u043b\u043e\u0439\u0442\u0430": "\u0414\u0430\u043d\u043d\u044b\u0435 \u0443\u0442\u043e\u0447\u043d\u044f\u044e\u0442\u0441\u044f",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "\u0418\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 \u043f\u043e\u0441\u043b\u0435 \u043e\u0441\u0432\u043e\u0431\u043e\u0436\u0434\u0435\u043d\u0438\u044f (CWE-416), \u0420\u0430\u0437\u044b\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u0443\u043a\u0430\u0437\u0430\u0442\u0435\u043b\u044f \u0441 \u0438\u0441\u0442\u0435\u043a\u0448\u0438\u043c \u0441\u0440\u043e\u043a\u043e\u043c \u0434\u0435\u0439\u0441\u0442\u0432\u0438\u044f (CWE-825)",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0444\u0443\u043d\u043a\u0446\u0438\u0438 p9_client_walk() \u043c\u043e\u0434\u0443\u043b\u044f net/9p/client.c \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0430 9P \u044f\u0434\u0440\u0430 \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u043e\u0439 \u0441\u0438\u0441\u0442\u0435\u043c\u044b Linux \u0441\u0432\u044f\u0437\u0430\u043d\u0430 \u0441 \u0440\u0430\u0437\u044b\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435\u043c \u0443\u043a\u0430\u0437\u0430\u0442\u0435\u043b\u044f \u0441 \u0438\u0441\u0442\u0435\u043a\u0448\u0438\u043c \u0441\u0440\u043e\u043a\u043e\u043c \u0434\u0435\u0439\u0441\u0442\u0432\u0438\u044f. \u042d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u043c\u043e\u0436\u0435\u0442 \u043f\u043e\u0437\u0432\u043e\u043b\u0438\u0442\u044c \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e, \u0434\u0435\u0439\u0441\u0442\u0432\u0443\u044e\u0449\u0435\u043c\u0443 \u0443\u0434\u0430\u043b\u0451\u043d\u043d\u043e, \u043e\u043a\u0430\u0437\u0430\u0442\u044c \u0432\u043e\u0437\u0434\u0435\u0439\u0441\u0442\u0432\u0438\u0435 \u043d\u0430 \u043a\u043e\u043d\u0444\u0438\u0434\u0435\u043d\u0446\u0438\u0430\u043b\u044c\u043d\u043e\u0441\u0442\u044c, \u0446\u0435\u043b\u043e\u0441\u0442\u043d\u043e\u0441\u0442\u044c \u0438 \u0434\u043e\u0441\u0442\u0443\u043f\u043d\u043e\u0441\u0442\u044c \u0437\u0430\u0449\u0438\u0449\u0430\u0435\u043c\u043e\u0439 \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u0438",
  "\u041f\u043e\u0441\u043b\u0435\u0434\u0441\u0442\u0432\u0438\u044f \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": null,
  "\u041f\u0440\u043e\u0447\u0430\u044f \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f": null,
  "\u0421\u0432\u044f\u0437\u044c \u0441 \u0438\u043d\u0446\u0438\u0434\u0435\u043d\u0442\u0430\u043c\u0438 \u0418\u0411": "\u0414\u0430\u043d\u043d\u044b\u0435 \u0443\u0442\u043e\u0447\u043d\u044f\u044e\u0442\u0441\u044f",
  "\u0421\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d\u0430",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044f": "\u041e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0435 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438": "\u041c\u0430\u043d\u0438\u043f\u0443\u043b\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0435 \u0441\u0442\u0440\u0443\u043a\u0442\u0443\u0440\u0430\u043c\u0438 \u0434\u0430\u043d\u043d\u044b\u0445",
  "\u0421\u0441\u044b\u043b\u043a\u0438 \u043d\u0430 \u0438\u0441\u0442\u043e\u0447\u043d\u0438\u043a\u0438": "https://www.cve.org/CVERecord?id=CVE-2026-63795\nhttps://git.kernel.org/linus/1a3860d46e3eb47dbd60339783cdad7904486b9f\nhttps://git.kernel.org/stable/c/99c379ca1e221c3d75c7c804ebbf4e5ee37a3070\nhttps://git.kernel.org/stable/c/b84f46179c806450b89821221ea5bd9a1698aba8\nhttps://git.kernel.org/stable/c/a61bdcba4f64c2f90d01461913f429ab151f1ca6\nhttps://git.kernel.org/stable/c/6dbe9443d9f5f7fb6d319a7b77108853ae6c6bea\nhttps://git.kernel.org/stable/c/a7656d368265d085ac9bb85ab31b0cdb72ad8c38\nhttps://security-tracker.debian.org/tracker/CVE-2026-63795\nhttps://ubuntu.com/security/CVE-2026-63795",
  "\u0421\u0442\u0430\u0442\u0443\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041f\u043e\u0434\u0442\u0432\u0435\u0440\u0436\u0434\u0435\u043d\u0430 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u0435\u043c",
  "\u0422\u0438\u043f \u041f\u041e": "\u041e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u0430\u044f \u0441\u0438\u0441\u0442\u0435\u043c\u0430",
  "\u0422\u0438\u043f \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "CWE-416, CWE-825",
  "\u0423\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041a\u0440\u0438\u0442\u0438\u0447\u0435\u0441\u043a\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 2.0 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 10)\n\u041a\u0440\u0438\u0442\u0438\u0447\u0435\u0441\u043a\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 3.1 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 10)"
}

CVE-2026-63795 (GCVE-0-2026-63795)

Vulnerability from cvelistv5 – Published: 2026-07-19 12:02 – Updated: 2026-08-17 04:51

Title

9p: avoid putting oldfid in p9_client_walk() error path

Summary

In the Linux kernel, the following vulnerability has been resolved: 9p: avoid putting oldfid in p9_client_walk() error path When p9_client_walk() is called with clone set to false, fid aliases oldfid. If the walk subsequently fails after the request has been sent, the error path jumps to clunk_fid, which currently calls p9_fid_put(fid) unconditionally. This drops a reference to oldfid even though ownership of oldfid remains with the caller. If this is the last reference, oldfid can be clunked and destroyed while the caller still expects it to be valid. A later use or put of oldfid can then trigger a use-after-free or refcount underflow. Fix this by only putting fid in the clunk_fid error path when it does not alias oldfid, matching the existing guard in the error path below. This can be triggered when a multi-component walk is split into multiple p9_client_walk() calls and a later non-cloning walk fails. A reproducer and refcount warning logs are available on request.

Severity

10 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Assigner

Linux mitre root

References

6 references

URL	Tags
https://git.kernel.org/stable/c/99c379ca1e221c3d7…
https://git.kernel.org/stable/c/b84f46179c806450b…
https://git.kernel.org/stable/c/a61bdcba4f64c2f90…
https://git.kernel.org/stable/c/6dbe9443d9f5f7fb6…
https://git.kernel.org/stable/c/a7656d368265d085a…
https://git.kernel.org/stable/c/1a3860d46e3eb47db…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: b48dbb998d70b7f48c2ec0a15c3cf47136808e4e , < 99c379ca1e221c3d75c7c804ebbf4e5ee37a3070 (git) Affected: b48dbb998d70b7f48c2ec0a15c3cf47136808e4e , < b84f46179c806450b89821221ea5bd9a1698aba8 (git) Affected: b48dbb998d70b7f48c2ec0a15c3cf47136808e4e , < a61bdcba4f64c2f90d01461913f429ab151f1ca6 (git) Affected: b48dbb998d70b7f48c2ec0a15c3cf47136808e4e , < 6dbe9443d9f5f7fb6d319a7b77108853ae6c6bea (git) Affected: b48dbb998d70b7f48c2ec0a15c3cf47136808e4e , < a7656d368265d085ac9bb85ab31b0cdb72ad8c38 (git) Affected: b48dbb998d70b7f48c2ec0a15c3cf47136808e4e , < 1a3860d46e3eb47dbd60339783cdad7904486b9f (git)
Linux	Linux	Affected: 6.0 Unaffected: 0 , < 6.0 (semver) Unaffected: 6.1.177 , ≤ 6.1.* (semver) Unaffected: 6.6.144 , ≤ 6.6.* (semver) Unaffected: 6.12.95 , ≤ 6.12.* (semver) Unaffected: 6.18.38 , ≤ 6.18.* (semver) Unaffected: 7.1.3 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/9p/client.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "99c379ca1e221c3d75c7c804ebbf4e5ee37a3070",
              "status": "affected",
              "version": "b48dbb998d70b7f48c2ec0a15c3cf47136808e4e",
              "versionType": "git"
            },
            {
              "lessThan": "b84f46179c806450b89821221ea5bd9a1698aba8",
              "status": "affected",
              "version": "b48dbb998d70b7f48c2ec0a15c3cf47136808e4e",
              "versionType": "git"
            },
            {
              "lessThan": "a61bdcba4f64c2f90d01461913f429ab151f1ca6",
              "status": "affected",
              "version": "b48dbb998d70b7f48c2ec0a15c3cf47136808e4e",
              "versionType": "git"
            },
            {
              "lessThan": "6dbe9443d9f5f7fb6d319a7b77108853ae6c6bea",
              "status": "affected",
              "version": "b48dbb998d70b7f48c2ec0a15c3cf47136808e4e",
              "versionType": "git"
            },
            {
              "lessThan": "a7656d368265d085ac9bb85ab31b0cdb72ad8c38",
              "status": "affected",
              "version": "b48dbb998d70b7f48c2ec0a15c3cf47136808e4e",
              "versionType": "git"
            },
            {
              "lessThan": "1a3860d46e3eb47dbd60339783cdad7904486b9f",
              "status": "affected",
              "version": "b48dbb998d70b7f48c2ec0a15c3cf47136808e4e",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/9p/client.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.177",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.144",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.95",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.38",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.177",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.144",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.95",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.38",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.3",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\n9p: avoid putting oldfid in p9_client_walk() error path\n\nWhen p9_client_walk() is called with clone set to false, fid aliases\noldfid. If the walk subsequently fails after the request has been sent,\nthe error path jumps to clunk_fid, which currently calls p9_fid_put(fid)\nunconditionally.\n\nThis drops a reference to oldfid even though ownership of oldfid remains\nwith the caller. If this is the last reference, oldfid can be clunked and\ndestroyed while the caller still expects it to be valid. A later use or\nput of oldfid can then trigger a use-after-free or refcount underflow.\n\nFix this by only putting fid in the clunk_fid error path when it does not\nalias oldfid, matching the existing guard in the error path below.\n\nThis can be triggered when a multi-component walk is split into multiple\np9_client_walk() calls and a later non-cloning walk fails. A reproducer\nand refcount warning logs are available on request."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 10,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The kernel 9p client processes TWALK responses from a remote 9p server over TCP/RDMA transports, and a malicious or compromised server can return a partial RWALK (nwqids \u003c nwname) or malformed reply to hit the clunk_fid error path during a multi-segment walk.\nAC:L - An attacker who controls the 9p server can reliably craft deep directory layouts and RWALK failure responses; the reproducer path (split multi-component walk with a failing non-cloning segment) does not depend on race timing or memory layout.\nPR:N - Exploitation only requires access to an already-mounted 9p filesystem and normal file operations (lookup/stat/open) that trigger v9fs_fid_lookup(); no elevated kernel capabilities or real-root privileges are needed beyond filesystem access permissions.\nUI:N - No interactive victim action is required beyond routine file access on a pre-mounted 9p filesystem (common with virtio-9p in QEMU/KVM/Firecracker VMs where the mount is established at boot).\nS:C - A malicious remote 9p server operates outside the kernel client\u0027s security boundary, and successful exploitation corrupts kernel heap memory (struct p9_fid use-after-free), impacting the kernel beyond the 9p client\u0027s own scope.\nC:H - Premature p9_fid_put() can destroy oldfid while callers still hold dangling references, producing a heap use-after-free on struct p9_fid that is exploitable for arbitrary kernel memory disclosure.\nI:H - The use-after-free and refcount underflow on struct p9_fid provide heap corruption primitives that can be leveraged for arbitrary kernel writes and local privilege escalation.\nA:H - The bug can cause immediate kernel oops/panic from use-after-free or refcount underflow when the prematurely freed fid is subsequently accessed or put again."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:51:00.086Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/99c379ca1e221c3d75c7c804ebbf4e5ee37a3070"
        },
        {
          "url": "https://git.kernel.org/stable/c/b84f46179c806450b89821221ea5bd9a1698aba8"
        },
        {
          "url": "https://git.kernel.org/stable/c/a61bdcba4f64c2f90d01461913f429ab151f1ca6"
        },
        {
          "url": "https://git.kernel.org/stable/c/6dbe9443d9f5f7fb6d319a7b77108853ae6c6bea"
        },
        {
          "url": "https://git.kernel.org/stable/c/a7656d368265d085ac9bb85ab31b0cdb72ad8c38"
        },
        {
          "url": "https://git.kernel.org/stable/c/1a3860d46e3eb47dbd60339783cdad7904486b9f"
        }
      ],
      "title": "9p: avoid putting oldfid in p9_client_walk() error path",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63795",
    "datePublished": "2026-07-19T12:02:04.069Z",
    "dateReserved": "2026-07-19T07:54:57.012Z",
    "dateUpdated": "2026-08-17T04:51:00.086Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.