CVE-2026-46033

Summary

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.

Affected Software

Weaknesses

ADP Enrichment

kernel: crypto: authencesn - reject short ahash digests during instance creation

Additional References

• https://access.redhat.com/security/cve/CVE-2026-46033
• https://bugzilla.redhat.com/show_bug.cgi?id=2482000
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46033.json

References

• https://git.kernel.org/stable/c/77f59fb2d3aa33e90ec6cbbf45dcfb20ab82b1a9
• https://git.kernel.org/stable/c/2f31cd1e64a079c845bca31d2da7b3c90a311726
• https://git.kernel.org/stable/c/d4c6a6d08e70bb1083c7c405fc7faacbf19aebc0
• https://git.kernel.org/stable/c/b69933e97efea238ebbfcf70c2b1be1cd03f13e3
• https://git.kernel.org/stable/c/67f1f0933cc3d78dde222842bcad2778ec7a0b88
• https://git.kernel.org/stable/c/b42821c15445f93daea3e76ada682b2b7181c476
• https://git.kernel.org/stable/c/9aff81e8217e9de2929084b03b3c7f81988c112b
• https://git.kernel.org/stable/c/5db6ef9847717329f12c5ea8aba7e9f588a980c0

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