CVE-2025-3576: Krb5: kerberos rc4-hmac-md5 checksum vulnerability enabling message spoofing via md5 collisions

Severity: medium (CVSS 5.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-04-15 · updated 2026-09-01
Weakness: CWE-328

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

Red Hat OpenShift Container Platform 4.18: all versions
Red Hat Discovery 2: all versions — fixed in 2.0.0-1752592913
Red Hat Enterprise Linux 10: all versions — fixed in 0:1.21.3-8.el10_0
Red Hat Enterprise Linux 8: all versions — fixed in 0:1.18.2-32.el8_10
Red Hat Enterprise Linux 8.2 Advanced Update Support: all versions — fixed in 0:1.17-19.el8_2.3
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support: all versions — fixed in 0:1.18.2-9.el8_4.3
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On: all versions — fixed in 0:1.18.2-9.el8_4.3
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support: all versions — fixed in 0:1.18.2-16.el8_6.4
Red Hat Enterprise Linux 8.6 Telecommunications Update Service: all versions — fixed in 0:1.18.2-16.el8_6.4
Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions: all versions — fixed in 0:1.18.2-16.el8_6.4
Red Hat Enterprise Linux 8.8 Telecommunications Update Service: all versions — fixed in 0:1.18.2-26.el8_8.5
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions: all versions — fixed in 0:1.18.2-26.el8_8.5
Red Hat Enterprise Linux 9: all versions — fixed in 0:1.21.1-8.el9_6
Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions: all versions — fixed in 0:1.19.1-16.el9_0.4
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions: all versions — fixed in 0:1.20.1-9.el9_2.3
Red Hat Enterprise Linux 9.4 Extended Update Support: all versions — fixed in 0:1.21.1-2.el9_4.2

How to fix

Upgrade to a fixed version: Red Hat Discovery 2 2.0.0-1752592913; Red Hat Enterprise Linux 10 0:1.21.3-8.el10_0; Red Hat Enterprise Linux 8 0:1.18.2-32.el8_10; Red Hat Enterprise Linux 8.2 Advanced Update Support 0:1.17-19.el8_2.3; Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 0:1.18.2-9.el8_4.3; Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On 0:1.18.2-9.el8_4.3; Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 0:1.18.2-16.el8_6.4; Red Hat Enterprise Linux 8.6 Telecommunications Update Service 0:1.18.2-16.el8_6.4; Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions 0:1.18.2-16.el8_6.4; Red Hat Enterprise Linux 8.8 Telecommunications Update Service 0:1.18.2-26.el8_8.5; Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 0:1.18.2-26.el8_8.5; Red Hat Enterprise Linux 9 0:1.21.1-8.el9_6. Check the vendor advisory for mitigations.

References

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