ubuntu-cve-2026-27171
Vulnerability from osv_ubuntu
Published
2026-02-18 04:16
Modified
2026-06-25 17:13
Summary
Details

zlib before 1.3.2 allows CPU consumption via crc32_combine64 and crc32_combine_gen64 because x2nmodp can do right shifts within a loop that has no termination condition.

Severity
2.9 (Low)
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
N/A (UNKNOWN)
low
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "lib32z1",
            "binary_version": "1:1.3.dfsg-3.1ubuntu2.1"
          },
          {
            "binary_name": "lib64z1",
            "binary_version": "1:1.3.dfsg-3.1ubuntu2.1"
          },
          {
            "binary_name": "libminizip1t64",
            "binary_version": "1:1.3.dfsg-3.1ubuntu2.1"
          },
          {
            "binary_name": "libx32z1",
            "binary_version": "1:1.3.dfsg-3.1ubuntu2.1"
          },
          {
            "binary_name": "minizip",
            "binary_version": "1:1.3.dfsg-3.1ubuntu2.1"
          },
          {
            "binary_name": "zlib1g",
            "binary_version": "1:1.3.dfsg-3.1ubuntu2.1"
          }
        ],
        "priority_reason": "Resource consumption via API misuse only"
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "zlib",
        "purl": "pkg:deb/ubuntu/zlib@1:1.3.dfsg-3.1ubuntu2.1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.2.13.dfsg-1ubuntu5",
        "1:1.3.dfsg-3ubuntu1",
        "1:1.3.dfsg-3.1ubuntu1",
        "1:1.3.dfsg-3.1ubuntu2",
        "1:1.3.dfsg-3.1ubuntu2.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "lib32z1",
            "binary_version": "1:1.3.dfsg+really1.3.1-1ubuntu2"
          },
          {
            "binary_name": "lib64z1",
            "binary_version": "1:1.3.dfsg+really1.3.1-1ubuntu2"
          },
          {
            "binary_name": "libminizip1t64",
            "binary_version": "1:1.3.dfsg+really1.3.1-1ubuntu2"
          },
          {
            "binary_name": "libx32z1",
            "binary_version": "1:1.3.dfsg+really1.3.1-1ubuntu2"
          },
          {
            "binary_name": "minizip",
            "binary_version": "1:1.3.dfsg+really1.3.1-1ubuntu2"
          },
          {
            "binary_name": "zlib1g",
            "binary_version": "1:1.3.dfsg+really1.3.1-1ubuntu2"
          }
        ],
        "priority_reason": "Resource consumption via API misuse only"
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "zlib",
        "purl": "pkg:deb/ubuntu/zlib@1:1.3.dfsg+really1.3.1-1ubuntu2?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.3.dfsg+really1.3.1-1ubuntu1",
        "1:1.3.dfsg+really1.3.1-1ubuntu2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "lib32z1",
            "binary_version": "1:1.3.dfsg+really1.3.1-1ubuntu3"
          },
          {
            "binary_name": "lib64z1",
            "binary_version": "1:1.3.dfsg+really1.3.1-1ubuntu3"
          },
          {
            "binary_name": "libminizip1t64",
            "binary_version": "1:1.3.dfsg+really1.3.1-1ubuntu3"
          },
          {
            "binary_name": "libx32z1",
            "binary_version": "1:1.3.dfsg+really1.3.1-1ubuntu3"
          },
          {
            "binary_name": "minizip",
            "binary_version": "1:1.3.dfsg+really1.3.1-1ubuntu3"
          },
          {
            "binary_name": "zlib1g",
            "binary_version": "1:1.3.dfsg+really1.3.1-1ubuntu3"
          }
        ],
        "priority_reason": "Resource consumption via API misuse only"
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "zlib",
        "purl": "pkg:deb/ubuntu/zlib@1:1.3.dfsg+really1.3.1-1ubuntu3?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.3.dfsg+really1.3.1-1ubuntu2",
        "1:1.3.dfsg+really1.3.1-1ubuntu3"
      ]
    }
  ],
  "aliases": [],
  "details": "zlib before 1.3.2 allows CPU consumption via crc32_combine64 and crc32_combine_gen64 because x2nmodp can do right shifts within a loop that has no termination condition.",
  "id": "UBUNTU-CVE-2026-27171",
  "modified": "2026-06-25T17:13:58Z",
  "published": "2026-02-18T04:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-27171"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-27171"
    },
    {
      "type": "REPORT",
      "url": "https://7asecurity.com/blog/2026/02/zlib-7asecurity-audit/"
    },
    {
      "type": "REPORT",
      "url": "https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdf"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/madler/zlib/releases/tag/v1.3.2"
    },
    {
      "type": "REPORT",
      "url": "https://ostif.org/zlib-audit-complete/"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "low",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-27171"
  ]
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • 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.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • 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.


Detection rules are retrieved from Rulezet.