Vulnerability-Lookup

GHSA-W2H3-C2WJ-WHWM

Vulnerability from github – Published: 2026-08-19 06:31 – Updated: 2026-08-19 06:31

Details

An unprivileged local user can trigger a prison reference count underflow, which may cause the prison structure to be freed while still in use. When this is done on the jail host, the bug will generally result in an immediate panic. However, if the user is running in a jail, then it may be possible to exploit the bug to elevate privileges.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-49419"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-911"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-19T05:17:04Z",
    "severity": null
  },
  "details": "When the JAIL_AT_DESC flag is specified, kern_jail_set() and kern_jail_get() released the reference to the caller\u0027s current prison before looking up the jail descriptor.  If the descriptor lookup failed, error-handling paths released the same reference a second time.\n\nAn unprivileged local user can trigger a prison reference count underflow, which may cause the prison structure to be freed while still in use.  When this is done on the jail host, the bug will generally result in an immediate panic.  However, if the user is running in a jail, then it may be possible to exploit the bug to elevate privileges.",
  "id": "GHSA-w2h3-c2wj-whwm",
  "modified": "2026-08-19T06:31:17Z",
  "published": "2026-08-19T06:31:17Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-49419"
    },
    {
      "type": "WEB",
      "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:38.jail.asc"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-49419 (GCVE-0-2026-49419)

Vulnerability from cvelistv5 – Published: 2026-08-19 04:32 – Updated: 2026-08-19 04:32

Title

Jail reference count underflow

Summary

When the JAIL_AT_DESC flag is specified, kern_jail_set() and kern_jail_get() released the reference to the caller's current prison before looking up the jail descriptor. If the descriptor lookup failed, error-handling paths released the same reference a second time. An unprivileged local user can trigger a prison reference count underflow, which may cause the prison structure to be freed while still in use. When this is done on the jail host, the bug will generally result in an immediate panic. However, if the user is running in a jail, then it may be possible to exploit the bug to elevate privileges.

Severity

No CVSS data available.

CWE

CWE-911 - Improper Update of Reference Count

Assigner

freebsd mitre root

References

1 reference

URL	Tags
https://security.freebsd.org/advisories/FreeBSD-S…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
FreeBSD	FreeBSD	Affected: 15.1-RELEASE , < p1 (release) Affected: 15.0-RELEASE , < p11 (release)

Date Public

2026-06-30 20:00

Credits

Yuxiang Yang, Yizhou Zhao, Ao Wang, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM-5.1 from Z.ai

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "modules": [
            "jail"
          ],
          "product": "FreeBSD",
          "vendor": "FreeBSD",
          "versions": [
            {
              "lessThan": "p1",
              "status": "affected",
              "version": "15.1-RELEASE",
              "versionType": "release"
            },
            {
              "lessThan": "p11",
              "status": "affected",
              "version": "15.0-RELEASE",
              "versionType": "release"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Yuxiang Yang, Yizhou Zhao, Ao Wang, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM-5.1 from Z.ai"
        }
      ],
      "datePublic": "2026-06-30T20:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "When the JAIL_AT_DESC flag is specified, kern_jail_set() and kern_jail_get() released the reference to the caller\u0027s current prison before looking up the jail descriptor.  If the descriptor lookup failed, error-handling paths released the same reference a second time.\n\nAn unprivileged local user can trigger a prison reference count underflow, which may cause the prison structure to be freed while still in use.  When this is done on the jail host, the bug will generally result in an immediate panic.  However, if the user is running in a jail, then it may be possible to exploit the bug to elevate privileges."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-911",
              "description": "CWE-911: Improper Update of Reference Count",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T04:32:39.446Z",
        "orgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
        "shortName": "freebsd"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:38.jail.asc"
        }
      ],
      "title": "Jail reference count underflow",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
    "assignerShortName": "freebsd",
    "cveId": "CVE-2026-49419",
    "datePublished": "2026-08-19T04:32:39.446Z",
    "dateReserved": "2026-05-29T20:24:28.616Z",
    "dateUpdated": "2026-08-19T04:32:39.446Z",
    "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.

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GHSA-W2H3-C2WJ-WHWM

CVE-2026-49419 (GCVE-0-2026-49419)

Tags

Sightings

Nomenclature