CVE-2026-85091 (GCVE-0-2026-85091)

Vulnerability from cvelistv5 – Published: 2026-09-03 01:04 – Updated: 2026-09-03 13:21
VLAI
Title
zlib 1.3.1.2 through 1.3.2 Heap Buffer Overflow via gz_vacate
Summary
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.
Severity
8.3 (High)
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
7.4 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
SSVC
Exploitation: poc Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-03 13:21 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
zlib zlib Affected: 1.3.1.2 , ≤ 1.3.2 (custom)
    cpe:2.3:a:zlib:zlib:*:*:*:*:*:*:*:*
Create a notification for this product.
Date Public
2026-09-02 00:00
Credits
Ali Firas (thesmartshadow)
Show details on NVD website
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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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