CVE-2026-49419
Jail reference count underflow
- Published
- Updated
- Reserved
- Assigned by
- freebsd
Description
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.
Timeline
ID reserved
By freebsd
- 3 months later
· 3 months later
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.47% · top 59% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.
Weakness
Affected products
References (1)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-49419)Record last updated .