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squashfs-tools — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2021-40153

squashfs_opendir in unsquash-1.c in Squashfs-Tools 4.5 stores the filename in the directory entry; this is then used by unsquashfs to create the new file during the unsquash. The filename is not validated for traversal outside of the destination directory, and thus allows writing to locations outside of the destination.

Products
squashfs-tools
Affected versions
Not specified
Fixed versions
1:4.5-2
CVEs
CVE-2021-40153
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 00:39 UTC · Revision 1

Source evidence

DEBIAN-CVE-2021-40153

core-osv · Original source

Published 27 Aug 2021, 15:15 UTC

squashfs_opendir in unsquash-1.c in Squashfs-Tools 4.5 stores the filename in the directory entry; this is then used by unsquashfs to create the new file during the unsquash. The filename is not validated for traversal outside of the destination directory, and thus allows writing to locations outside of the destination.

osv:DEBIAN-CVE-2021-40153

squashfs-tools

Fixed versions: 1:4.5-2

squashfs-tools

Fixed versions: 1:4.5-2

squashfs-tools

Fixed versions: 1:4.5-2

Complete source record
{
  "id": "c38e5ae448f4a842888bbb801dff4374c938d09c3e33d395f299e484d7399d3a",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-40153",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2021-40153",
    "summary": "squashfs_opendir in unsquash-1.c in Squashfs-Tools 4.5 stores the filename in the directory entry; this is then used by unsquashfs to create the new file during the unsquash. The filename is not validated for traversal outside of the destination directory, and thus allows writing to locations outside of the destination.",
    "evidence": "osv:DEBIAN-CVE-2021-40153",
    "products": [
      {
        "name": {
          "value": "squashfs-tools",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:4.5-2",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "squashfs-tools",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:4.5-2",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "squashfs-tools",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:4.5-2",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "DEBIAN-CVE-2021-40153",
      "aliases": [
        "DEBIAN-CVE-2021-40153"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:4.5-2"
                }
              ]
            }
          ],
          "package": {
            "name": "squashfs-tools",
            "purl": "pkg:deb/debian/squashfs-tools?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-40153.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:4.5-2"
                }
              ]
            }
          ],
          "package": {
            "name": "squashfs-tools",
            "purl": "pkg:deb/debian/squashfs-tools?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-40153.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:4.5-2"
                }
              ]
            }
          ],
          "package": {
            "name": "squashfs-tools",
            "purl": "pkg:deb/debian/squashfs-tools?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-40153.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-23T18:03:32.652020255Z",
      "provider": "osv",
      "upstream": [
        "CVE-2021-40153"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2021-40153"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2021-40153",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 421860,
  "published_at": "2021-08-27T15:15:09.657+00:00"
}