CVE-2026-49427 json
posixshm: largepage shared memory objects not explicitly wired
published 2026-08-19 2 mo ago modified 2026-09-01 2 mo ago also EUVD-2026-62254
- cvss
- 8.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 43%
- public exploits
- 0
- none known
Summary
Pages belonging to largepage shared memory objects were not explicitly wired. When sendfile(2) transmitted such an object with the SF_NOCACHE flag, it freed the underlying pages after transmission even though existing mappings still referred to them.
An unprivileged local user can abuse the bug to access freed kernel memory. This can be exploited to escalate privileges.
Patch / fix
- FreeBSD FreeBSD p1, p7, p11, p16
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 2 mo ago
Exploit prediction
0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| CNA | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected products
- FreeBSD FreeBSD
Classification
- Weakness
-
- CWE-826 Premature Release of Resource During Expected Lifetime
References
-
security.freebsd.org
/advisories/FreeBSD-SA-26:44.posixshm.asc
vendor-advisory
Sources
- CVE List CVE-2026-49427
- NVD CVE-2026-49427
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