Fix CVE(s): CVE-2020-23922, CVE-2021-40633, CVE-2026-23868

{
  "id": "1d81a258c7c62cfc7dc1b9542578082bd87cff4677697b73667282e27c9171d0",
  "url": "https://osv.dev/vulnerability/CLSA-2026-1787646995",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Fix CVE(s): CVE-2020-23922, CVE-2021-40633, CVE-2026-23868",
    "summary": "* SECURITY UPDATE: heap buffer over-read in gif2rgb - debian/patches/CVE-2020-23922.patch: bound each pixel index against the active color table before indexing ColorMap->Colors in DumpScreen2RGB in util/gif2rgb.c. - CVE-2020-23922 * SECURITY UPDATE: memory leak leading to denial of service - debian/patches/CVE-2021-40633.patch: free every ScreenBuffer row, not just the row-pointer array, at the end of GIF2RGB in util/gif2rgb.c. - CVE-2021-40633 * SECURITY UPDATE: double free in GifMakeSavedImage - debian/patches/CVE-2026-23868.patch: null out the heap pointers aliased by the shallow copy of CopyFrom, test the source record when deciding what to deep-copy, and restore ExtensionBlockCount after the extension blocks are copied, in lib/gifalloc.c. - CVE-2026-23868",
    "evidence": "osv:CLSA-2026-1787646995",
    "products": [
      {
        "name": {
          "value": "giflib-tools",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.1.4-2ubuntu0.1+tuxcare.els1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "libgif-dev",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.1.4-2ubuntu0.1+tuxcare.els1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "libgif7",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.1.4-2ubuntu0.1+tuxcare.els1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CLSA-2026-1787646995",
      "aliases": [
        "CLSA-2026-1787646995"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5.1.4-2ubuntu0.1+tuxcare.els1"
                }
              ]
            }
          ],
          "package": {
            "name": "giflib-tools",
            "purl": "pkg:deb/tuxcare/giflib-tools?distro=ubuntu-18.04",
            "ecosystem": "TuxCare:Ubuntu:18.04"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu18.04els/CLSA-2026-1787646995.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5.1.4-2ubuntu0.1+tuxcare.els1"
                }
              ]
            }
          ],
          "package": {
            "name": "libgif-dev",
            "purl": "pkg:deb/tuxcare/libgif-dev?distro=ubuntu-18.04",
            "ecosystem": "TuxCare:Ubuntu:18.04"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu18.04els/CLSA-2026-1787646995.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5.1.4-2ubuntu0.1+tuxcare.els1"
                }
              ]
            }
          ],
          "package": {
            "name": "libgif7",
            "purl": "pkg:deb/tuxcare/libgif7?distro=ubuntu-18.04",
            "ecosystem": "TuxCare:Ubuntu:18.04"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu18.04els/CLSA-2026-1787646995.json"
          }
        }
      ],
      "modified": "2026-10-26T09:30:42.804789392Z",
      "provider": "osv",
      "upstream": [
        "CVE-2020-23922",
        "CVE-2021-40633",
        "CVE-2026-23868"
      ],
      "references": [
        "https://errata.tuxcare.com/els_os/ubuntu18.04els/CLSA-2026-1787646995.html",
        "https://nvd.nist.gov/vuln/detail/CVE-2020-23922",
        "https://nvd.nist.gov/vuln/detail/CVE-2021-40633",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-23868"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2020-23922",
        "evidence": "/upstream"
      },
      {
        "value": "CVE-2021-40633",
        "evidence": "/upstream"
      },
      {
        "value": "CVE-2026-23868",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 447193,
  "published_at": "2026-08-25T08:36:48+00:00"
}