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Medium

Archive spoofing vulnerability in borgbackup

Type: advisorySources: OSV

borgbackup is an opensource, deduplicating archiver with compression and authenticated encryption. A flaw in the cryptographic authentication scheme in borgbackup allowed an attacker to fake archives and potentially indirectly cause backup data loss in the repository. The attack requires an attacker to be able to: 1. insert files (with no additional headers) into backups and 2. gain write access to the repository. This vulnerability does not disclose plaintext to the attacker, nor does it affect the authenticity of existing archives. Creating plausible fake archives may be feasible for empty or small archives, but is unlikely for large archives. The issue has been fixed in borgbackup 1.2.5. Users are advised to upgrade. Additionally to installing the fixed code, users must follow the upgrade procedure as documented in the change log. Data loss after being attacked can be avoided by reviewing the archives (timestamp and contents valid and as expected) after any "borg check --repair" and before "borg prune". There are no known workarounds for this vulnerability.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2023-36811
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 14:51 UTC · Revision 1

Source evidence

Archive spoofing vulnerability in borgbackup

core-osv · Original source

Published 30 Aug 2023, 17:32 UTC

borgbackup is an opensource, deduplicating archiver with compression and authenticated encryption. A flaw in the cryptographic authentication scheme in borgbackup allowed an attacker to fake archives and potentially indirectly cause backup data loss in the repository. The attack requires an attacker to be able to: 1. insert files (with no additional headers) into backups and 2. gain write access to the repository. This vulnerability does not disclose plaintext to the attacker, nor does it affect the authenticity of existing archives. Creating plausible fake archives may be feasible for empty or small archives, but is unlikely for large archives. The issue has been fixed in borgbackup 1.2.5. Users are advised to upgrade. Additionally to installing the fixed code, users must follow the upgrade procedure as documented in the change log. Data loss after being attacked can be avoided by reviewing the archives (timestamp and contents valid and as expected) after any "borg check --repair" and before "borg prune". There are no known workarounds for this vulnerability.

osv:CVE-2023-36811
Complete source record
{
  "id": "8d8c3caf0ce853303f947cf96d651752b57bcd050b4989c9ba5e0324de45059f",
  "url": "https://osv.dev/vulnerability/CVE-2023-36811",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Archive spoofing vulnerability in borgbackup",
    "summary": "borgbackup is an opensource, deduplicating archiver with compression and authenticated encryption. A flaw in the cryptographic authentication scheme in borgbackup allowed an attacker to fake archives and potentially indirectly cause backup data loss in the repository. The attack requires an attacker to be able to: 1. insert files (with no additional headers) into backups and 2. gain write access to the repository. This vulnerability does not disclose plaintext to the attacker, nor does it affect the authenticity of existing archives. Creating plausible fake archives may be feasible for empty or small archives, but is unlikely for large archives. The issue has been fixed in borgbackup 1.2.5. Users are advised to upgrade. Additionally to installing the fixed code, users must follow the upgrade procedure as documented in the change log. Data loss after being attacked can be avoided by reviewing the archives (timestamp and contents valid and as expected) after any \"borg check --repair\" and before \"borg prune\". There are no known workarounds for this vulnerability.",
    "evidence": "osv:CVE-2023-36811",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2023-36811",
      "aliases": [
        "CVE-2023-36811",
        "GHSA-8fjr-hghr-4m99",
        "PYSEC-2023-164"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/borgbackup/borg",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "447d0df1bbc323cc0af35be674bdcf1dd3124c72"
                },
                {
                  "fixed": "3eb070191da10c2d3f7bc6484cf3d51c3045f884"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:borgbackup:borg:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.2.5"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "3eb070191da10c2d3f7bc6484cf3d51c3045f884"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.2.5-cvedocs",
            "2.0.0.dev0",
            "1.3.0dev0",
            "1.2.0",
            "1.2.0dev0",
            "1.1.0.dev0",
            "1.1.0b1",
            "1.1.dev0",
            "1.0.0",
            "1.0.0rc2",
            "1.0.0rc1",
            "0.30.0",
            "0.29.0",
            "0.28.2",
            "0.28.1",
            "0.28.0",
            "0.27.0",
            "0.26.1",
            "0.26.0",
            "0.25.0",
            "0.24.0",
            "0.23.0",
            "0.14",
            "0.13",
            "0.12",
            "0.11",
            "0.10",
            "0.9",
            "0.8.1",
            "0.8",
            "0.7",
            "0.6.1",
            "0.6"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-36811.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:29.827453766Z",
      "provider": "osv",
      "references": [
        "https://github.com/borgbackup/borg/blob/1.2.5-cvedocs/docs/changes.rst#pre-125-archives-spoofing-vulnerability-cve-2023-36811",
        "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5Q3OHXERTU547SEQ3YREZXHOCYNLVD63/",
        "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XOZDFIYEBIOKSIEAXUJJJFUJTAJ7TF3C/",
        "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZUCQSMAWOJBCRGF6XPKEZ2TPGAPNKIWV/",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/36xxx/CVE-2023-36811.json",
        "https://github.com/borgbackup/borg/security/advisories/GHSA-8fjr-hghr-4m99",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-36811",
        "https://github.com/borgbackup/borg/commit/3eb070191da10c2d3f7bc6484cf3d51c3045f884"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-347"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/36xxx/CVE-2023-36811.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-36811",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 496549,
  "published_at": "2023-08-30T17:32:06.215+00:00"
}