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.
Metrics
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History
Fri, 16 Jan 2026 18:30:00 +0000
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Fri, 16 Jan 2026 15:00:00 +0000
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| 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. |
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Fri, 16 Jan 2026 00:15:00 +0000
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threat_severity
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threat_severity
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Thu, 15 Jan 2026 08:15:00 +0000
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Gnu
Gnu glibc |
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Gnu
Gnu glibc |
Wed, 14 Jan 2026 22:15:00 +0000
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cvssV3_1
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Wed, 14 Jan 2026 21:15:00 +0000
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| 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 | |
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Status: PUBLISHED
Assigner: glibc
Published: 2026-01-14T21:01:11.037Z
Updated: 2026-01-16T17:06:42.010Z
Reserved: 2026-01-12T14:35:11.285Z
Link: CVE-2026-0861
Updated: 2026-01-16T17:06:42.010Z
Status : Awaiting Analysis
Published: 2026-01-14T21:15:52.617
Modified: 2026-01-16T18:16:09.343
Link: CVE-2026-0861