High

DEBIAN-CVE-2026-85091

Type: advisorySource: OSV1 source record

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.

Announced 3 Sept 2026Group revision 1

Original source ↗

DEBIAN-CVE-2026-85091

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:DEBIAN-CVE-2026-85091

zlib

Source reference: /affected/0/package/name

Affected versions: 1:1.2.13.dfsg-1
Source reference: /affected/0/versions
1:1.2.13.dfsg-2
Source reference: /affected/0/versions
1:1.2.13.dfsg-3
Source reference: /affected/0/versions
1:1.3.dfsg+really1.3.1-1
Source reference: /affected/0/versions
1:1.3.dfsg+really1.3.1-2
Source reference: /affected/0/versions
1:1.3.dfsg+really1.3.1-3
Source reference: /affected/0/versions
1:1.3.dfsg+really1.3.2-1
Source reference: /affected/0/versions
1:1.3.dfsg+really1.3.2-2
Source reference: /affected/0/versions
1:1.3.dfsg+really1.3.2-3
Source reference: /affected/0/versions
1:1.3.dfsg-1
Source reference: /affected/0/versions
1:1.3.dfsg-2
Source reference: /affected/0/versions
1:1.3.dfsg-3
Source reference: /affected/0/versions
1:1.3.dfsg-3.1
Source reference: /affected/0/versions
1:1.3.dfsg-3.1~exp1
Source reference: /affected/0/versions
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

zlib

Source reference: /affected/1/package/name

Affected versions: 1:1.3.dfsg+really1.3.1-1
Source reference: /affected/1/versions
1:1.3.dfsg+really1.3.1-2
Source reference: /affected/1/versions
1:1.3.dfsg+really1.3.1-3
Source reference: /affected/1/versions
1:1.3.dfsg+really1.3.2-1
Source reference: /affected/1/versions
1:1.3.dfsg+really1.3.2-2
Source reference: /affected/1/versions
1:1.3.dfsg+really1.3.2-3
Source reference: /affected/1/versions
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

zlib

Source reference: /affected/2/package/name

Affected versions: 1:1.3.dfsg+really1.3.1-1
Source reference: /affected/2/versions
1:1.3.dfsg+really1.3.1-2
Source reference: /affected/2/versions
1:1.3.dfsg+really1.3.1-3
Source reference: /affected/2/versions
1:1.3.dfsg+really1.3.2-1
Source reference: /affected/2/versions
1:1.3.dfsg+really1.3.2-2
Source reference: /affected/2/versions
1:1.3.dfsg+really1.3.2-3
Source reference: /affected/2/versions
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "zlib",
      "purl": "pkg:deb/debian/zlib?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "1:1.2.13.dfsg-1",
      "1:1.2.13.dfsg-2",
      "1:1.2.13.dfsg-3",
      "1:1.3.dfsg+really1.3.1-1",
      "1:1.3.dfsg+really1.3.1-2",
      "1:1.3.dfsg+really1.3.1-3",
      "1:1.3.dfsg+really1.3.2-1",
      "1:1.3.dfsg+really1.3.2-2",
      "1:1.3.dfsg+really1.3.2-3",
      "1:1.3.dfsg-1",
      "1:1.3.dfsg-2",
      "1:1.3.dfsg-3",
      "1:1.3.dfsg-3.1",
      "1:1.3.dfsg-3.1~exp1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-85091.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "zlib",
      "purl": "pkg:deb/debian/zlib?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "1:1.3.dfsg+really1.3.1-1",
      "1:1.3.dfsg+really1.3.1-2",
      "1:1.3.dfsg+really1.3.1-3",
      "1:1.3.dfsg+really1.3.2-1",
      "1:1.3.dfsg+really1.3.2-2",
      "1:1.3.dfsg+really1.3.2-3"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-85091.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "zlib",
      "purl": "pkg:deb/debian/zlib?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "1:1.3.dfsg+really1.3.1-1",
      "1:1.3.dfsg+really1.3.1-2",
      "1:1.3.dfsg+really1.3.1-3",
      "1:1.3.dfsg+really1.3.2-1",
      "1:1.3.dfsg+really1.3.2-2",
      "1:1.3.dfsg+really1.3.2-3"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-85091.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Related CVEs: CVE-2026-85091
Source reference: /upstream

Publisher severity

high

Source reference: /severity/0/score

Event: #81501 · Revision 1
Added to Heist Feed: Mon, 26 Oct 2026 15:56:33 GMT
Publisher date: Thu, 03 Sep 2026 13:06:20 GMT

Read the original announcement

Revision history

26 Oct 2026DEBIAN-CVE-2026-85091 · Revision 1Source updated