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.
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History

Fri, 16 Jan 2026 18:30:00 +0000

Type Values Removed Values Added
References

Fri, 16 Jan 2026 15:00:00 +0000

Type Values Removed Values Added
Description Passing too large an alignment to the memalign suite of functions (memalign, posix_memalign, aligned_alloc, valloc, pvalloc) 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. 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.
References

Fri, 16 Jan 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Thu, 15 Jan 2026 08:15:00 +0000

Type Values Removed Values Added
First Time appeared Gnu
Gnu glibc
Vendors & Products Gnu
Gnu glibc

Wed, 14 Jan 2026 22:15:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 8.4, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 14 Jan 2026 21:15:00 +0000

Type Values Removed Values Added
Description Passing too large an alignment to the memalign suite of functions (memalign, posix_memalign, aligned_alloc, valloc, pvalloc) 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.
Title Integer overflow in memalign leads to heap corruption
Weaknesses CWE-190
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: glibc

Published:

Updated: 2026-01-16T17:06:42.010Z

Reserved: 2026-01-12T14:35:11.285Z

Link: CVE-2026-0861

cve-icon Vulnrichment

Updated: 2026-01-16T17:06:42.010Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-01-14T21:15:52.617

Modified: 2026-01-16T18:16:09.343

Link: CVE-2026-0861

cve-icon Redhat

Severity : Important

Publid Date: 2026-01-14T21:01:11Z

Links: CVE-2026-0861 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-01-15T08:03:18Z

Weaknesses