BDU:2026-03457 (CVE-2025-61920)
Vulnerability from fstec – Published: 2026-03-23 – Updated: 2026-03-23 – View on bdu.fstec.ru Fixed
VLAI
Title
Уязвимость реализации JOSE библиотеки Authlib для серверов OAuth и OpenID Connect, позволяющая нарушителю вызвать отказ в обслуживании
Summary
Уязвимость реализации JOSE библиотеки Authlib для серверов OAuth и OpenID Connect связана с недостаточной проверкой вводимых данных. Эксплуатация уязвимости может позволить нарушителю, действующему удаленно, вызвать отказ в обслуживании
Severity
Class
Code vulnerability
Status
Confirmed by the vendor
Exploitation
Resource manipulation, Resource exhaustion
Incidents
Being clarified
Remediation
Software update
CWE
Aliases
References
9 references
Impacted products
5 products
from 6 vendors
Vendors
Сообщество свободного программного обеспечения, Canonical Ltd., ООО «Ред Софт», Red Hat, Inc., Hsiaoming Ltd
Products
Debian GNU/Linux, Ubuntu, РЕД ОС (запись в едином реестре российских программ №3751), Red Hat Quay, Аuthlib
Versions
11 (Debian GNU/Linux), 22.04 LTS (Ubuntu), 24.04 LTS (Ubuntu), 25.10 (Ubuntu), 8.0 (РЕД ОС), 3.1 (Red Hat Quay), 3.12 (Red Hat Quay), 3.9 (Red Hat Quay), 3.13 (Red Hat Quay), 3.14 (Red Hat Quay), до 1.6.5 (Аuthlib)
Product types
Operating system, Application software
Platforms
Сообщество свободного программного обеспечения Debian GNU/Linux 11, Canonical Ltd. Ubuntu 22.04 LTS, Canonical Ltd. Ubuntu 24.04 LTS, Canonical Ltd. Ubuntu 25.10, ООО «Ред Софт» РЕД ОС 8.0 (запись в едином реестре российских программ №3751)
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 Authlib:
https://docs.authlib.org/en/stable/changelog.html#version-1-6-5
Для Debian GNU/Linux:
https://security-tracker.debian.org/tracker/CVE-2025-61920
Для программных продуктов Red Hat Inc.:
https://access.redhat.com/security/cve/cve-2025-61920
Для Ubuntu:
https://ubuntu.com/security/CVE-2025-61920
Для Ред ОС:
http://repo.red-soft.ru/redos/8.0/x86_64/updates/
{
"CVSS 2.0": "AV:N/AC:L/Au:N/C:N/I:N/A:C",
"CVSS 3.0": "AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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., \u041e\u041e\u041e \u00ab\u0420\u0435\u0434 \u0421\u043e\u0444\u0442\u00bb, Red Hat, Inc., Hsiaoming Ltd",
"\u0412\u0435\u0440\u0441\u0438\u044f \u041f\u041e": "11 (Debian GNU/Linux), 22.04 LTS (Ubuntu), 24.04 LTS (Ubuntu), 25.10 (Ubuntu), 8.0 (\u0420\u0415\u0414 \u041e\u0421), 3.1 (Red Hat Quay), 3.12 (Red Hat Quay), 3.9 (Red Hat Quay), 3.13 (Red Hat Quay), 3.14 (Red Hat Quay), \u0434\u043e 1.6.5 (\u0410uthlib)",
"\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 Authlib:\nhttps://docs.authlib.org/en/stable/changelog.html#version-1-6-5\n\n\u0414\u043b\u044f Debian GNU/Linux:\nhttps://security-tracker.debian.org/tracker/CVE-2025-61920\n\n\u0414\u043b\u044f \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u044b\u0445 \u043f\u0440\u043e\u0434\u0443\u043a\u0442\u043e\u0432 Red Hat Inc.:\nhttps://access.redhat.com/security/cve/cve-2025-61920\n\n\u0414\u043b\u044f Ubuntu:\nhttps://ubuntu.com/security/CVE-2025-61920\n\n\u0414\u043b\u044f \u0420\u0435\u0434 \u041e\u0421: \nhttp://repo.red-soft.ru/redos/8.0/x86_64/updates/",
"\u0414\u0430\u0442\u0430 \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0438\u044f": "02.10.2025",
"\u0414\u0430\u0442\u0430 \u043f\u043e\u0441\u043b\u0435\u0434\u043d\u0435\u0433\u043e \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f": "23.03.2026",
"\u0414\u0430\u0442\u0430 \u043f\u0443\u0431\u043b\u0438\u043a\u0430\u0446\u0438\u0438": "23.03.2026",
"\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": "BDU:2026-03457",
"\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-2025-61920, GHSA-pq5p-34cr-23v9",
"\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, \u0420\u0415\u0414 \u041e\u0421 (\u0437\u0430\u043f\u0438\u0441\u044c \u0432 \u0435\u0434\u0438\u043d\u043e\u043c \u0440\u0435\u0435\u0441\u0442\u0440\u0435 \u0440\u043e\u0441\u0441\u0438\u0439\u0441\u043a\u0438\u0445 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c \u21163751), Red Hat Quay, \u0410uthlib",
"\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 , Canonical Ltd. Ubuntu 22.04 LTS , Canonical Ltd. Ubuntu 24.04 LTS , Canonical Ltd. Ubuntu 25.10 , \u041e\u041e\u041e \u00ab\u0420\u0435\u0434 \u0421\u043e\u0444\u0442\u00bb \u0420\u0415\u0414 \u041e\u0421 8.0 (\u0437\u0430\u043f\u0438\u0441\u044c \u0432 \u0435\u0434\u0438\u043d\u043e\u043c \u0440\u0435\u0435\u0441\u0442\u0440\u0435 \u0440\u043e\u0441\u0441\u0438\u0439\u0441\u043a\u0438\u0445 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c \u21163751)",
"\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 \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 JOSE \u0431\u0438\u0431\u043b\u0438\u043e\u0442\u0435\u043a\u0438 Authlib \u0434\u043b\u044f \u0441\u0435\u0440\u0432\u0435\u0440\u043e\u0432 OAuth \u0438 OpenID Connect, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u0432\u044b\u0437\u0432\u0430\u0442\u044c \u043e\u0442\u043a\u0430\u0437 \u0432 \u043e\u0431\u0441\u043b\u0443\u0436\u0438\u0432\u0430\u043d\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": "\u041d\u0435\u0434\u043e\u0441\u0442\u0430\u0442\u043e\u0447\u043d\u0430\u044f \u043f\u0440\u043e\u0432\u0435\u0440\u043a\u0430 \u0432\u0432\u043e\u0434\u0438\u043c\u044b\u0445 \u0434\u0430\u043d\u043d\u044b\u0445 (CWE-20), \u041d\u0435\u043a\u043e\u043d\u0442\u0440\u043e\u043b\u0438\u0440\u0443\u0435\u043c\u044b\u0439 \u0440\u0430\u0441\u0445\u043e\u0434 \u0440\u0435\u0441\u0443\u0440\u0441\u0430 (\u00ab\u0418\u0441\u0442\u043e\u0449\u0435\u043d\u0438\u0435 \u0440\u0435\u0441\u0443\u0440\u0441\u0430\u00bb) (CWE-400), \u041d\u0435\u043e\u0433\u0440\u0430\u043d\u0438\u0447\u0435\u043d\u043d\u043e\u0435 \u0440\u0430\u0441\u043f\u0440\u0435\u0434\u0435\u043b\u0435\u043d\u0438\u0435 \u0440\u0435\u0441\u0443\u0440\u0441\u043e\u0432 \u0438\u043b\u0438 \u0434\u0440\u043e\u0441\u0441\u0435\u043b\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0435 (CWE-770)",
"\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 \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 JOSE \u0431\u0438\u0431\u043b\u0438\u043e\u0442\u0435\u043a\u0438 Authlib \u0434\u043b\u044f \u0441\u0435\u0440\u0432\u0435\u0440\u043e\u0432 OAuth \u0438 OpenID Connect \u0441\u0432\u044f\u0437\u0430\u043d\u0430 \u0441 \u043d\u0435\u0434\u043e\u0441\u0442\u0430\u0442\u043e\u0447\u043d\u043e\u0439 \u043f\u0440\u043e\u0432\u0435\u0440\u043a\u043e\u0439 \u0432\u0432\u043e\u0434\u0438\u043c\u044b\u0445 \u0434\u0430\u043d\u043d\u044b\u0445. \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\u0435\u043d\u043d\u043e, \u0432\u044b\u0437\u0432\u0430\u0442\u044c \u043e\u0442\u043a\u0430\u0437 \u0432 \u043e\u0431\u0441\u043b\u0443\u0436\u0438\u0432\u0430\u043d\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 \u0440\u0435\u0441\u0443\u0440\u0441\u0430\u043c\u0438, \u0418\u0441\u0447\u0435\u0440\u043f\u0430\u043d\u0438\u0435 \u0440\u0435\u0441\u0443\u0440\u0441\u043e\u0432",
"\u0421\u0441\u044b\u043b\u043a\u0438 \u043d\u0430 \u0438\u0441\u0442\u043e\u0447\u043d\u0438\u043a\u0438": "https://github.com/authlib/authlib\nhttps://github.com/authlib/authlib/commit/867e3f87b072347a1ae9cf6983cc8bbf88447e5e\nhttps://github.com/authlib/authlib/security/advisories/GHSA-pq5p-34cr-23v9\nhttps://lists.debian.org/debian-lts-announce/2025/10/msg00032.html\nhttps://docs.authlib.org/en/stable/changelog.html#version-1-6-5\nhttp://repo.red-soft.ru/redos/8.0/x86_64/updates/\nhttps://security-tracker.debian.org/tracker/CVE-2025-61920\nhttps://access.redhat.com/security/cve/cve-2025-61920\nhttps://ubuntu.com/security/CVE-2025-61920",
"\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, \u041f\u0440\u0438\u043a\u043b\u0430\u0434\u043d\u043e\u0435 \u041f\u041e \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u043e\u043d\u043d\u044b\u0445 \u0441\u0438\u0441\u0442\u0435\u043c",
"\u0422\u0438\u043f \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "CWE-20, CWE-400, CWE-770",
"\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": "\u0412\u044b\u0441\u043e\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 7,8)\n\u0412\u044b\u0441\u043e\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 7,5)"
}
CVE-2025-61920 (GCVE-0-2025-61920)
Vulnerability from cvelistv5 – Published: 2025-10-10 19:25 – Updated: 2025-11-03 17:45
VLAI
EPSS
VEX
Title
Authlib is vulnerable to Denial of Service via Oversized JOSE Segments
Summary
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.5, Authlib’s JOSE implementation accepts unbounded JWS/JWT header and signature segments. A remote attacker can craft a token whose base64url‑encoded header or signature spans hundreds of megabytes. During verification, Authlib decodes and parses the full input before it is rejected, driving CPU and memory consumption to hostile levels and enabling denial of service. Version 1.6.5 patches the issue. Some temporary workarounds are available. Enforce input size limits before handing tokens to Authlib and/or use application-level throttling to reduce amplification risk.
Severity
7.5 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-10-10 20:46 UTC
CWE
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/authlib/authlib/security/advis… | x_refsource_CONFIRM |
| https://github.com/authlib/authlib/commit/867e3f8… | x_refsource_MISC |
| https://lists.debian.org/debian-lts-announce/2025… |
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2025-61920",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2025-10-10T20:46:55.883426Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2025-10-10T20:47:08.736Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
},
{
"providerMetadata": {
"dateUpdated": "2025-11-03T17:45:23.708Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00032.html"
}
],
"title": "CVE Program Container"
}
],
"cna": {
"affected": [
{
"product": "authlib",
"vendor": "authlib",
"versions": [
{
"status": "affected",
"version": "\u003c 1.6.5"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.5, Authlib\u2019s JOSE implementation accepts unbounded JWS/JWT header and signature segments. A remote attacker can craft a token whose base64url\u2011encoded header or signature spans hundreds of megabytes. During verification, Authlib decodes and parses the full input before it is rejected, driving CPU and memory consumption to hostile levels and enabling denial of service. Version 1.6.5 patches the issue. Some temporary workarounds are available. Enforce input size limits before handing tokens to Authlib and/or use application-level throttling to reduce amplification risk."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-20",
"description": "CWE-20: Improper Input Validation",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-400",
"description": "CWE-400: Uncontrolled Resource Consumption",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-770",
"description": "CWE-770: Allocation of Resources Without Limits or Throttling",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2025-10-10T19:25:07.679Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/authlib/authlib/security/advisories/GHSA-pq5p-34cr-23v9",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/authlib/authlib/security/advisories/GHSA-pq5p-34cr-23v9"
},
{
"name": "https://github.com/authlib/authlib/commit/867e3f87b072347a1ae9cf6983cc8bbf88447e5e",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/authlib/authlib/commit/867e3f87b072347a1ae9cf6983cc8bbf88447e5e"
}
],
"source": {
"advisory": "GHSA-pq5p-34cr-23v9",
"discovery": "UNKNOWN"
},
"title": "Authlib is vulnerable to Denial of Service via Oversized JOSE Segments"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2025-61920",
"datePublished": "2025-10-10T19:25:07.679Z",
"dateReserved": "2025-10-03T22:21:59.615Z",
"dateUpdated": "2025-11-03T17:45:23.708Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
GHSA-PQ5P-34CR-23V9
Vulnerability from github – Published: 2025-10-10 20:26 – Updated: 2025-11-03 18:31
VLAI
Summary
Authlib is vulnerable to Denial of Service via Oversized JOSE Segments
Details
Summary Authlib’s JOSE implementation accepts unbounded JWS/JWT header and signature segments. A remote attacker can craft a token whose base64url‑encoded header or signature spans hundreds of megabytes. During verification, Authlib decodes and parses the full input before it is rejected, driving CPU and memory consumption to hostile levels and enabling denial of service.
Impact
-
Attack vector: unauthenticated network attacker submits a malicious JWS/JWT.
-
Effect: base64 decode + JSON/crypto processing of huge buffers pegs CPU and allocates large amounts of RAM; a single request can exhaust service capacity.
-
Observed behaviour: on a test host, the legacy code verified a 500 MB header, consuming ~4 GB RSS and ~9 s CPU before failing.
-
Severity: High. CVSS v3.1: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (7.5).
Affected Versions Authlib ≤ 1.6.3 (and earlier) when verifying JWS/JWT tokens. Later snapshots with 256 KB header/signature limits are not affected.
Proof of concept
Local demo (do not run against third-party systems): Download jws_segment_dos_demo.py the PoC in direcotry authlib/ Run following Command
python3 jws_segment_dos_demo.py --variant both --sizes "500MB" --fork-per-case
Environment: Python 3.13.6, Authlib 1.6.4, Linux x86_64, CPUs=8
Sample output: Refined
The compilation script prints separate “[ATTACKER]” (token construction) and “[SERVER]” (Authlib verification) RSS deltas so defenders can distinguish client-side preparation from server-side amplification. Regression tests authlib/tests/dos/test_jose_dos.py further capture the issue; the saved original_util.py/original_jws.py reproductions still accept the malicious payload.
Remediation
-
Apply the upstream patch that introduces decoded size limits:
-
MAX_HEADER_SEGMENT_BYTES = 256 KB
-
MAX_SIGNATURE_SEGMENT_BYTES = 256 KB
-
Enforce Limits in authlib/jose/util.extract_segment and _extract_signature.
-
Deploy the patched release immediately.
-
For additional defence in depth, reject JWS/JWT inputs above a few kilobytes at the proxy or WAF layer, and rate-limit verification endpoints.
Workarounds (temporary)
-
Enforce input size limits before handing tokens to Authlib.
-
Use application-level throttling to reduce amplification risk.
Resources
-
Demo script: jws_segment_dos_demo.py
-
Tests: authlib/tests/dos/test_jose_dos.py
-
OWASP JWT Cheat Sheet (DoS guidance)
Severity
7.5 (High)
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "authlib"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.6.5"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-61920"
],
"database_specific": {
"cwe_ids": [
"CWE-20",
"CWE-400",
"CWE-770"
],
"github_reviewed": true,
"github_reviewed_at": "2025-10-10T20:26:43Z",
"nvd_published_at": "2025-10-10T20:15:37Z",
"severity": "HIGH"
},
"details": "**Summary**\nAuthlib\u2019s JOSE implementation accepts unbounded JWS/JWT header and signature segments. A remote attacker can craft a token whose base64url\u2011encoded header or signature spans hundreds of megabytes. During verification, Authlib decodes and parses the full input before it is rejected, driving CPU and memory consumption to hostile levels and enabling denial of service.\n\n**Impact**\n\n- Attack vector: unauthenticated network attacker submits a malicious JWS/JWT.\n\n- Effect: base64 decode + JSON/crypto processing of huge buffers pegs CPU and allocates large amounts of RAM; a single request can exhaust service capacity.\n\n- Observed behaviour: on a test host, the legacy code verified a 500\u202fMB header, consuming ~4\u202fGB RSS and ~9\u202fs CPU before failing.\n\n- Severity: High. CVSS v3.1: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (7.5).\n\nAffected Versions\nAuthlib \u2264\u202f1.6.3 (and earlier) when verifying JWS/JWT tokens. Later snapshots with 256\u202fKB header/signature limits are not affected.\n\n**Proof of concept**\n\nLocal demo (do not run against third-party systems):\nDownload [jws_segment_dos_demo.py](https://github.com/user-attachments/files/22450820/jws_segment_dos_demo.py) the PoC in direcotry authlib/\nRun following Command\n```\npython3 jws_segment_dos_demo.py --variant both --sizes \"500MB\" --fork-per-case\n\n```\nEnvironment: Python 3.13.6, Authlib 1.6.4, Linux x86_64, CPUs=8 \nSample output: Refined\n\u003cimg width=\"1295\" height=\"306\" alt=\"image\" src=\"https://github.com/user-attachments/assets/6dd8410f-bc36-4717-8cee-649bac9bf291\" /\u003e\n\n\n\n\nThe compilation script prints separate \u201c[ATTACKER]\u201d (token construction) and \u201c[SERVER]\u201d (Authlib verification) RSS deltas so defenders can distinguish client-side preparation from server-side amplification. Regression tests authlib/tests/dos/test_jose_dos.py further capture the issue; the saved original_util.py/original_jws.py reproductions still accept the malicious payload.\n\n**Remediation**\n\n- Apply the upstream patch that introduces decoded size limits:\n\n- MAX_HEADER_SEGMENT_BYTES = 256 KB\n\n- MAX_SIGNATURE_SEGMENT_BYTES = 256 KB\n\n- Enforce Limits in authlib/jose/util.extract_segment and _extract_signature.\n\n- Deploy the patched release immediately.\n\n- For additional defence in depth, reject JWS/JWT inputs above a few kilobytes at the proxy or WAF layer, and rate-limit verification endpoints.\n\n**Workarounds (temporary)**\n\n- Enforce input size limits before handing tokens to Authlib.\n\n- Use application-level throttling to reduce amplification risk.\n\n**Resources**\n\n- Demo script: jws_segment_dos_demo.py\n\n- Tests: authlib/tests/dos/test_jose_dos.py\n\n- OWASP JWT Cheat Sheet (DoS guidance)",
"id": "GHSA-pq5p-34cr-23v9",
"modified": "2025-11-03T18:31:46Z",
"published": "2025-10-10T20:26:43Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/authlib/authlib/security/advisories/GHSA-pq5p-34cr-23v9"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-61920"
},
{
"type": "WEB",
"url": "https://github.com/authlib/authlib/commit/867e3f87b072347a1ae9cf6983cc8bbf88447e5e"
},
{
"type": "PACKAGE",
"url": "https://github.com/authlib/authlib"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00032.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "Authlib is vulnerable to Denial of Service via Oversized JOSE Segments"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
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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.
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.
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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.
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