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🛡️ CVE-2026-0861 — glibc

🟠 CVSS 8.4 — High ⚠️ Exploit Public CWE-190 NVD
8.4
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Passing too large an alignment to the memalign suite of functions (memalign, posix_memalign, aligned_alloc) in the GNU C Library version 2.30 to 2.42 may result in an integer overflow, which could consequently result in a heap corruption.

Note that the attacker must have control over both, the size as well as the alignment arguments of the memalign function to be able to exploit this. The size parameter must be close enough to PTRDIFF_MAX so as to overflow size_t along with the large alignment argument. This limits the malicious inputs for the alignment for memalign to the range [1<<62+ 1, 1<<63] and exactly 1<<63 for posix_memalign and aligned_alloc.

Typically the alignment argument passed to such functions is a known constrained quantity (e.g. page size, block size, struct sizes) and is not attacker controlled, because of which this may not be easily exploitable in practice. An application bug could potentially result in the input alignment being too large, e.g. due to a different buffer overflow or integer overflow in the application or its dependent libraries, but that is again an uncommon usage pattern given typical sources of alignments.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Local — a local account, shell or session on the host is needed.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2026-0861 is classified as CWE-190: Integer Overflow or Wraparound. Arithmetic produces a value too large for its type and wraps around, so a later size or bounds check passes when it should not.

Affected software

CVE-2026-0861 is recorded against 1 package.

  • glibc (from 2.30 up to 2.42)

Timeline and source

Published on 14 January 2026 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. A vendor advisory or fix has been published. Record sourced from NVD.

References

sourceware.org
sourceware.org
www.openwall.com

Other advisories for this package

glibc has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-190: Integer Overflow or Wraparound) in other software:

Details

Severity HIGH
CVSS Score 8.4
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE CWE-190
Public Exploit ⚠️ Yes
Source NVD
Published 2026-01-14
Updated 2026-08-20
Modified 2026-06-17

Affected Packages

Software From version Fixed in
glibc 2.30 2.42

Similar Threats

Exploit Protection

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CVE-2026-0861 carries CVSS 8.4 High rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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