CVE-2026-31719 crypto: krb5enc - fix async decrypt skipping hash verification

What is CVE-2026-31719?

CVE-2026-31719 is a high-severity vulnerability in Linux kernel, published on 1 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

crypto: krb5enc - fix async decrypt skipping hash verification

krb5enc_dispatch_decrypt() sets req->base.complete as the skcipher callback, which is the caller's own completion handler. When the skcipher completes asynchronously, this signals "done" to the caller without executing krb5enc_dispatch_decrypt_hash(), completely bypassing the integrity verification (hash check).

Compare with the encrypt path which correctly uses krb5enc_encrypt_done as an intermediate callback to chain into the hash computation on async completion.

Fix by adding krb5enc_decrypt_done as an intermediate callback that chains into krb5enc_dispatch_decrypt_hash() upon async skcipher completion, matching the encrypt path's callback pattern.

Also fix EBUSY/EINPROGRESS handling throughout: remove krb5enc_request_complete() which incorrectly swallowed EINPROGRESS notifications that must be passed up to callers waiting on backlogged requests, and add missing EBUSY checks in krb5enc_encrypt_ahash_done for the dispatch_encrypt return value.

Unset MAY_BACKLOG on the async completion path so the user won't see back-to-back EINPROGRESS notifications.

Weakness: CWE-354

Which versions are affected by CVE-2026-31719?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-31719?

Apply the vendor's patch.

Is CVE-2026-31719 being exploited?

There is no known exploitation of CVE-2026-31719 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-31719, DEBIAN-CVE-2026-31719, GHSA-774g-v4gm-8h6v, UBUNTU-CVE-2026-31719.