The Linux kernel’s Kerberos encryption helper (krb5enc) previously allowed an asynchronous decryption operation to skip the hash verification step. During async completion the kernel called the caller’s completion handler directly, bypassing the additional hash‑check function that would normally confirm the integrity of the decrypted data. This flaw meant that forged or tampered ciphertext could be accepted as valid, undermining the integrity guarantees of Kerberos authentication and related encrypted data exchanges.

All Linux kernel releases that include the affected krb5enc path prior to the commit fixing the async decrypt hash verification are vulnerable. The CVE entry indicates that the problem resides in the kernel crypto stack for the Linux vendor’s generic kernel package, impacting every distribution that ships the default Linux kernel without the patch.

The vulnerability is a missing integrity check (CWE-325) and can be exercised via the Kerberos async decryption interface, which user‑space Kerberos libraries typically invoke. The CVSS score of 7.0 signals high severity, and while the EPSS score is not available and the issue is not listed in the CISA KEV catalog, the potential to subvert authentication and data integrity is significant. Attacks are likely to arise from malicious or compromised Kerberos clients or services that can provide crafted ciphertext to the kernel’s decryption helper.