zlib 1.2.11 through 1.3.2 contains a heap buffer overflow: after an underlying write() fails, gz_write() returns without resetting strm.next_in, leaving it pointed at the caller's buffer. A later gz* write call then derives a position from the stale pointer and writes past a heap allocation; any write() failure reaches it, including EPIPE on a blocking descriptor, and in versions before 1.3.1.2 the failed write must be followed by a gzclearerr() call.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 1
- First seenCVSS 8.3NVD modified 2026-10-12 17:10
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 5
- https://gist.github.com/thesmartshadow/e0b9481792afb7c31e86fee1ff084490
- https://github.com/madler/zlib
- https://github.com/madler/zlib/blob/v1.3.2/gzwrite.c#L393
- https://github.com/madler/zlib/commit/df84af25dc1942490e1d1c899a07619152a46148
- https://www.vulncheck.com/advisories/zlib-1.3.1.2-through-1.3.2-heap-buffer-overflow-via-gz-vacate