CVE-2026-49424

Kernel stack disclosure via uninitialized siginfo copy

Published Aug 19, 2026 · Updated Aug 19, 2026

FreeBSD 14.3-RELEASE before p16, 14.4-RELEASE before p7, and 15.0-RELEASE before p11 allow local users to read kernel stack data via waitid(). In sys/compat/linux/linux_misc.c, linux_common_wait() stack-allocates a Linux siginfo_t, passes it through siginfo_to_lsiginfo(), and copies it to user space without memset zeroing unused bytes first. Exposure requires the Linux binary compatibility layer to be present; the published impact is disclosure of 104 bytes of leftover kernel stack data, with no stated overwrite or execution path.

CVSS severityUnavailable
Unscored
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

FreeBSD 14.3-RELEASE before p16, 14.4-RELEASE before p7, and 15.0-RELEASE before p11 allow local users to read kernel stack data via waitid(). In sys/compat/linux/linux_misc.c, linux_common_wait() stack-allocates a Linux siginfo_t, passes it through siginfo_to_lsiginfo(), and copies it to user space without memset zeroing unused bytes first. Exposure requires the Linux binary compatibility layer to be present; the published impact is disclosure of 104 bytes of leftover kernel stack data, with no stated overwrite or execution path.

The record

CVE
CVE-2026-49424
Published
Aug 19, 2026
Updated
Aug 19, 2026
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-908
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=14.3-RELEASE <p16
  2. Affected versionversion=14.4-RELEASE <p7
  3. Affected versionversion=15.0-RELEASE <p11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The FreeBSD Project · FreeBSDversion=14.3-RELEASE <p16; version=14.4-RELEASE <p7; version=15.0-RELEASE <p11

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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