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Medium

Security advisory

Type: advisorySources: OSVCVE: CVE-2021-3521

There is a flaw in RPM's signature functionality. OpenPGP subkeys are associated with a primary key via a "binding signature." RPM does not check the binding signature of subkeys prior to importing them. If an attacker is able to add or socially engineer another party to add a malicious subkey to a legitimate public key, RPM could wrongly trust a malicious signature. The greatest impact of this flaw is to data integrity. To exploit this flaw, an attacker must either compromise an RPM repository or convince an administrator to install an untrusted RPM or public key. It is strongly recommended to only use RPMs and public keys from trusted sources.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2021-3521
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 12:45 UTC · Revision 1

Source evidence

CVE-2021-3521

core-osv · Original source

Published 22 Aug 2022, 15:15 UTC

There is a flaw in RPM's signature functionality. OpenPGP subkeys are associated with a primary key via a "binding signature." RPM does not check the binding signature of subkeys prior to importing them. If an attacker is able to add or socially engineer another party to add a malicious subkey to a legitimate public key, RPM could wrongly trust a malicious signature. The greatest impact of this flaw is to data integrity. To exploit this flaw, an attacker must either compromise an RPM repository or convince an administrator to install an untrusted RPM or public key. It is strongly recommended to only use RPMs and public keys from trusted sources.

osv:CVE-2021-3521
Complete source record
{
  "id": "31478ace3d44ea18c9c5e4f802d23e7b46d91aef3ed915581c05d33eb701c14b",
  "url": "https://osv.dev/vulnerability/CVE-2021-3521",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-3521",
    "summary": "There is a flaw in RPM's signature functionality. OpenPGP subkeys are associated with a primary key via a \"binding signature.\" RPM does not check the binding signature of subkeys prior to importing them. If an attacker is able to add or socially engineer another party to add a malicious subkey to a legitimate public key, RPM could wrongly trust a malicious signature. The greatest impact of this flaw is to data integrity. To exploit this flaw, an attacker must either compromise an RPM repository or convince an administrator to install an untrusted RPM or public key. It is strongly recommended to only use RPMs and public keys from trusted sources.",
    "evidence": "osv:CVE-2021-3521",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-3521",
      "aliases": [
        "CVE-2021-3521"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/rpm-software-management/rpm",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5bef402da334595ed9302b8bca1acdf5e88bfe11"
                },
                {
                  "fixed": "bd36c5dc9fb6d90c46fbfed8c2d67516fc571ec8"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:rpm:rpm:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "4.17.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "bd36c5dc9fb6d90c46fbfed8c2d67516fc571ec8"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "rpm-4.17.0-release",
            "rpm-4.17.0-rc1",
            "rpm-4.17.0-beta1",
            "rpm-4.17.0-alpha",
            "rpm-4.16.0-alpha",
            "rpm-4.15.0-alpha",
            "rpm-4.13.0-alpha",
            "rpm-4.12.0-alpha",
            "rpm-4.11.0-alpha",
            "rpm-4.8.0-beta1",
            "rpm-4.4.2.1-rc2",
            "rpm-4.4.2.1-rc1",
            "rpm-4.4.2-release",
            "rpm-4.4.1-release",
            "rpm-4.4-release"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3521.json",
            "vanir_signatures": [
              {
                "id": "CVE-2021-3521-1b22a8d2",
                "digest": {
                  "length": 659,
                  "function_hash": "18654273305198649316022720889848845896"
                },
                "source": "https://github.com/rpm-software-management/rpm/commit/bd36c5dc9fb6d90c46fbfed8c2d67516fc571ec8",
                "target": {
                  "file": "rpmio/rpmpgp.c",
                  "function": "pgpPrtParams"
                },
                "deprecated": false,
                "signature_type": "Function",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2021-3521-90ac71c4",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
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                  ]
                },
                "source": "https://github.com/rpm-software-management/rpm/commit/bd36c5dc9fb6d90c46fbfed8c2d67516fc571ec8",
                "target": {
                  "file": "rpmio/rpmpgp.c"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-20T14:25:21Z"
          }
        }
      ],
      "modified": "2026-10-20T14:25:21.643454591Z",
      "provider": "osv",
      "references": [
        "https://access.redhat.com/security/cve/CVE-2021-3521",
        "https://security.gentoo.org/glsa/202210-22",
        "https://bugzilla.redhat.com/show_bug.cgi?id=1941098",
        "https://github.com/rpm-software-management/rpm/commit/bd36c5dc9fb6d90c46fbfed8c2d67516fc571ec8",
        "https://github.com/rpm-software-management/rpm/pull/1795/"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-3521",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 388975,
  "published_at": "2022-08-22T15:15:13.473+00:00"
}