#1146895 zlib: CVE-2026-85091

Package:
src:zlib
Source:
src:zlib
Submitter:
Salvatore Bonaccorso
Date:
2026-09-07 15:51:01 UTC
Severity:
normal
Tags:
#1146895#5
Date:
2026-09-06 19:02:48 UTC
From:
To:
Hi,

The following vulnerability was published for zlib.

CVE-2026-85091[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.


If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-85091
https://www.cve.org/CVERecord?id=CVE-2026-85091
[1] https://gist.github.com/thesmartshadow/e0b9481792afb7c31e86fee1ff084490
[2] https://github.com/madler/zlib/commit/e3dc0a85b7032e98380dec011bc8f2c2ee0d8fca

Regards,
Salvatore
#1146895#10
Date:
2026-09-06 19:21:59 UTC
From:
To:
Hi,

FWIW, [2] might not be correct, can you check with upstream?

Regards,
Salvatore