CVE-2026-74578

A flaw was found in the Linux kernel's algif_skcipher cryptographic module. An unprivileged local user could exploit a race condition in the asynchronous I/O (AIO) path, where a concurrent operation overwrites the Initialization Vector (IV) used by an in-flight cryptographic request. This IV reuse allows the attacker to recover the plaintext of concurrent cryptographic operations, leading to information disclosure.

A race in crypto algif_skcipher allows the async skcipher_recvmsg() path to pass the socket wide ctx iv directly into an in flight skcipher request. After io_submit() the socket lock can be dropped while the request is still processed, so a concurrent sendmsg(ALG_SET_IV) can replace ctx iv and make the operation run with attacker controlled IV material. For CTR and stream like modes this can cause IV or keystream reuse and may allow recovery of plaintext from a concurrent operation. For the CVSS the PR:L is used because triggering requires a local process that can use AF_ALG sockets and submit the racing operations, but no administrative privileges are required in typical configurations. The issue is not network reachable by itself and affects local crypto API users. Impact is mainly confidentiality loss and possible integrity impact through attacker controlled IV selection, not kernel code execution or a direct privilege escalation.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

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