CVE-2026-74578

Technical Description

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

crypto: algif_skcipher - force synchronous processing on trees without ctx->state

The AIO/async path in skcipher_recvmsg() passes the socket-wide ctx->iv

directly into the skcipher request. After io_submit() the socket lock is

dropped and the request is processed asynchronously, so a concurrent

sendmsg(ALG_SET_IV) can overwrite ctx->iv and make the in-flight request

run under an attacker-controlled IV. For CTR/stream modes this is

IV/keystream reuse and lets an unprivileged user recover the plaintext of

a concurrent operation.

Snapshotting ctx->iv into per-request storage for the async path is not

sufficient. For ciphers with statesize == 0 - which includes cbc and ctr -

the MSG_MORE inter-chunk IV chaining is carried solely by the in-place

req->iv writeback, which a snapshot redirects into per-request memory that

af_alg_free_resources() releases on completion, silently producing wrong

output. Writing the IV back fr

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References