What’s Vulnerable › Vulnerabilities
CVE-2021-3521
- Severity: medium (CVSS 4.7 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.3% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2022-08-22 · updated 2026-06-17
- Weakness: CWE-347
Description
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.
Affected products
- RPM: before 4.17.1 — fixed in 4.17.1
How to fix
Upgrade to a fixed version: RPM 4.17.1. Check the vendor advisory for mitigations.
References
- https://access.redhat.com/security/cve/CVE-2021-3521
- 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/
- https://security.gentoo.org/glsa/202210-22
- https://access.redhat.com/security/cve/CVE-2021-3521
- 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/
- https://security.gentoo.org/glsa/202210-22
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