CVE-2025-3576

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.

• krb5 1.21.2-1 (bug https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1103525) [bookworm] - krb5 (Minor issue) https://bugzilla.redhat.com/show_bug.cgi?id=2359465 CVE relates to issues covered in: https://i.blackhat.com/EU-22/Thursday-Briefings/EU-22-Tervoort-Breaking-Kerberos-RC4-Cipher-and-Spoofing-Windows-PACs-wp.pdf Since upstream 1.21 (cf. https://web.mit.edu/kerberos/krb5-1.21/) the KDC will no longer issue tickets with RC4 or triple-DES session keys unless explicitly configured with the new allow_rc4 or allow_des3 variables respectively. https://github.com/krb5/krb5/commit/1b57a4d134bbd0e7c52d5885a92eccc815726463 https://github.com/krb5/krb5/commit/2cbd847e0e92bc4e219b65c770ae33f851b22afc