CVE-2021-20271

Package database corruption via unchecked signature tags

Published Mar 26, 2021 · Updated Aug 3, 2024

Signature verification bypass in RPM Package Manager allows attackers to corrupt the package database through a modified signed package. headerMergeLegacySigs() copies unknown signature-header tags into package metadata without validating each tag's expected type and size. Exploitation requires a compromised repository or an administrator installing an untrusted package; resulting corruption can hide installed packages and dependencies but is repairable.

CVSS severity6.7
Medium
EPSS probability0.79%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Signature verification bypass in RPM Package Manager allows attackers to corrupt the package database through a modified signed package. headerMergeLegacySigs() copies unknown signature-header tags into package metadata without validating each tag's expected type and size. Exploitation requires a compromised repository or an administrator installing an untrusted package; resulting corruption can hide installed packages and dependencies but is repairable.

The record

CVE
CVE-2021-20271
Published
Mar 26, 2021
Updated
Aug 3, 2024
Vendor
RPM Software Management
Product
RPM Package Manager
Classifications
CWE-345, T1195.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=all versions

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

RPM Software Management · RPM Package Managerversion=all versions

Published CVSS scores

6.7Red Hat, Inc.CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H
5.1NIST NVDAV:N/AC:H/Au:N/C:P/I:P/A:P
7.0NIST NVDCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-345Insufficient Verification of Data Authenticity
T1195.002Compromise Software Supply Chain

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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