CVE-2026-46033

Description

In the Linux kernel, the following vulnerability has been resolved: crypto: authencesn - reject short ahash digests during instance creation authencesn requires either a zero authsize or an authsize of at least 4 bytes because the ESN encrypt/decrypt paths always move 4 bytes of high-order sequence number data at the end of the authenticated data. While crypto_authenc_esn_setauthsize() already rejects explicit non-zero authsizes in the range 1..3, crypto_authenc_esn_create() still copied auth->digestsize into inst->alg.maxauthsize without validating it. The AEAD core then initialized the tfm's default authsize from that value. As a result, selecting an ahash with digest size 1..3, such as cbcmac(cipher_null), exposed authencesn instances whose default authsize was invalid even though setauthsize() would have rejected the same value. AF_ALG could then trigger the ESN tail handling with a too-short tag and hit an out-of-bounds access. Reject authencesn instances whose ahash digest size is in the invalid non-zero range 1..3 so that no tfm can inherit an unsupported default authsize.

References

• https://git.kernel.org/stable/c/5db6ef9847717329f12c5ea8aba7e9f588a980c0
• https://git.kernel.org/stable/c/67f1f0933cc3d78dde222842bcad2778ec7a0b88
• https://git.kernel.org/stable/c/9aff81e8217e9de2929084b03b3c7f81988c112b
• https://git.kernel.org/stable/c/b42821c15445f93daea3e76ada682b2b7181c476
• https://git.kernel.org/stable/c/b69933e97efea238ebbfcf70c2b1be1cd03f13e3