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MEDIUM

Krb5: kerberos rc4-hmac-md5 checksum vulnerability enabling message spoofing via md5 collisions

Published Apr 15, 2025

Description

A vulnerability in the MIT Kerberos implementation allows GSSAPI-protected messages using RC4-HMAC-MD5 to be spoofed due to weaknesses in the MD5 checksum design. If RC4 is preferred over stronger encryption types, an attacker could exploit MD5 collisions to forge message integrity codes. This may lead to unauthorized message tampering.

Affected products

Remediation

Vendor solution

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Red Hat statement

This issue is classified as a moderate severity vulnerability because it affects the handling of PKINIT requests during ASN.1 decoding in krb5. Exploitation requires specific and uncommon configurations, including a Kerberos environment with PKINIT enabled. Additionally, successful exploitation depends on triggering specific memory allocation failures or parser behaviors, contributing to a high attack complexity.The attack requires that PKINIT is actively configured and in use, and cannot be exploited remotely without this setup in place, making the practical risk limited in standard environments.

Red Hat mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Weaknesses (1)

CWE-328

References (19)

Change history (0)

No recorded changes yet.

Sources
CVE.org / MITRE
Status PUBLISHED
Assigner redhat
Published Apr 15, 2025
Updated Sep 1, 2026
Reserved Apr 14, 2025
Link CVE-2025-3576
CISA Vulnrichment
Updated Apr 15, 2025
NVD
Status Deferred
Modified Sep 1, 2026
Link CVE-2025-3576
Red Hat
Severity Moderate
Public date Apr 15, 2025
Links CVE-2025-3576 - Bugzilla
ENISA EUVD
Assigner redhat
Published Apr 15, 2025
Updated Sep 1, 2026
Exploited since n/a
Link EUVD-2025-10925
EUVD-2025-10925