CVE-2026-49428

posixshm: system calls can incorrectly free memory of largepage objects

HIGH
8.4
CVSS Score
Published: August 19, 2026 at 05:57 AM UTC
Updated: September 1, 2026 at 08:21 PM UTC
1 product affected across 1 vendorFreeBSD

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Severity
HIGH8.4
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

Certain system calls, such open(2) with the O_TRUNC flag set, and fspacectl(2), could incorrectly free memory in largepage objects. These operations are not permitted on largepage objects, but the implementation did not verify this. An unprivileged local user can abuse the bug to access freed kernel memory. This can be exploited to escalate privileges.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Affected range stops below p1, so it looks safe — our inference, not a vendor statement
Affected range stops below p11, so it looks safe — our inference, not a vendor statement
Affected range stops below p16, so it looks safe — our inference, not a vendor statement
Affected range stops below p7, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.4HIGHCISA-ADP
Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-915

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