CVE-2026-85091 — zlib 1.3.1.2 through 1.3.2 Heap Buffer Overflow via gz_vacate
zlib versions 1.3.1.2 through 1.3.2 contain a heap buffer overflow vulnerability in the gz_vacate() function when processing non-blocking gzwrite() operations with stale externa…
Published: 2026-09-03 · CVSS: 8.3 · CVSS 4.0
zlib versions 1.3.1.2 through 1.3.2 contain a heap buffer overflow vulnerability in the gz_vacate() function when processing non-blocking gzwrite() operations with stale external buffer pointers. Attackers can trigger the overflow by calling gzprintf() or gzvprintf() after a write stall, causing an unchecked memmove() to write beyond the internal input buffer boundary.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7