CVE-2026-0861 Integer overflow in memalign leads to heap corruption
An integer overflow in glibc's memalign functions can lead to heap corruption, potentially allowing code execution if an attacker controls both size and alignment arguments.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-0861?
CVE-2026-0861 is a high-severity vulnerability in Gnu Glibc, published on 14 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-190
Which versions are affected by CVE-2026-0861?
It affects 1 product.
Linux distribution packages (4)
glibc-livepatches SUSE:Linux Enterprise Live Patching 15 SP4 | All versions | 0.3-150400.3.11.1 |
glibc-livepatches SUSE:Linux Enterprise Live Patching 15 SP5 | All versions | 0.3-150400.3.11.1 |
glibc-livepatches SUSE:Linux Enterprise Live Patching 15 SP6 | All versions | 0.3-150600.8.2.1 |
glibc-livepatches SUSE:Linux Enterprise Live Patching 15 SP7 | All versions | 0.3-150700.10.4.1 |
Products include Gnu Glibc.
How do I fix CVE-2026-0861?
Upgrade to a fixed version.
Is CVE-2026-0861 being exploited?
There is no known exploitation of CVE-2026-0861 in the wild and no public exploit code.
Other vulnerabilities in Gnu Glibc
Sources
Also known as AZL-74547, AZL-74636, BELL-CVE-2026-0861, CLSA-2026-1770741856, CLSA-2026-1772463357, DEBIAN-CVE-2026-0861 and 11 more.