High severity · published Jan 14, 2026
CVE-2026-0861
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…
8.4
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 33% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
GL
Glibc · Gnu
2.30 through 2.42 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-0861
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-0861
Exploit
https://sourceware.org/bugzilla/show_bug.cgi?id=33796
Patch
https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0001
Mailing List
http://www.openwall.com/lists/oss-security/2026/01/16/5
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