The malloc function in the GNU C Library (aka glibc or libc6) 2.26 could return a memory block that is too small if an attempt is made to allocate an object whose size is close to SIZE_MAX, potentially leading to a subsequent heap overflow. This occurs because the per-thread cache (aka tcache) feature enables a code path that lacks an integer overflow check.
Severity
CVSS 3.0
8.1 high
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
1.6% chance of exploitation in the next 30 days; higher than 75% of CVEs (scores of 2026-10-31)