High severity · published Aug 19, 2026
CVE-2026-49427
posixshm: largepage shared memory objects not explicitly wired
8.8
CVSS
0.5%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
FreeBSD · FreeBSD
15.1-RELEASE before p1; 15.0-RELEASE before p11; 14.4-RELEASE before p7; 14.3-RELEASE before p16 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-49427
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-49427
Vendor Advisory
https://security.freebsd.org/advisories/FreeBSD-SA-26:44.posixshm.asc
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