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Vulnerability · Published Aug 22, 2022 · Assigned by redhat

CVE-2021-3521

Medium 4.7

In plain English

A medium-severity security flaw in RPM. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 26% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)4.7Medium
Exploit odds (30 days)0.3%top 74.3% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:8rpm-build4.14.3-19.el8_5.2ALSA-2022:0368
AlmaLinux:8rpm-plugin-fapolicyd4.14.3-19.el8_5.2ALSA-2022:0368
Alpine:v3.20rpm4.17.1-r0ALPINE-CVE-2021-3521
Alpine:v3.21rpm4.17.1-r0ALPINE-CVE-2021-3521
Alpine:v3.22rpm4.17.1-r0ALPINE-CVE-2021-3521
Alpine:v3.23rpm4.17.1-r0ALPINE-CVE-2021-3521
Alpine:v3.24rpm4.17.1-r0ALPINE-CVE-2021-3521
Debian:12rpm4.18.0+dfsg-1DEBIAN-CVE-2021-3521
Debian:13rpm4.18.0+dfsg-1DEBIAN-CVE-2021-3521
Debian:14rpm4.18.0+dfsg-1DEBIAN-CVE-2021-3521
Rocky Linux:8rpm0:4.14.3-19.el8_5.2RLSA-2022:0368
Ubuntu:22.04:LTSrpmno fix listedUBUNTU-CVE-2021-3521
Ubuntu:24.04:LTSrpmno fix listedUBUNTU-CVE-2021-3521
Ubuntu:25.10rpmno fix listedUBUNTU-CVE-2021-3521
Ubuntu:26.04:LTSrpmno fix listedUBUNTU-CVE-2021-3521
Ubuntu:26.10rpmno fix listedUBUNTU-CVE-2021-3521

Affected products (as reported)

VendorProductVersions
n/a RPM Fixed in rpm-4.18.0-beta1, rpm-4.18.0-alpha2, rpm-4.18.0-alpha1 .

Weakness: CWE-347

References