CVE-2026-46033: In the Linux kernel, the following vulnerability has been resolved: crypto: authencesn - reject short ahash digests during instance creation authenc...

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.

Metrics

CVSS 3.1

7.1/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

EPSS Probability

0.13%

2.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-125

Affected Software

Vendor	Product	Versions	Update
Linux	Linux Kernel	>= 4.11, < 5.10.258	—
Linux	Linux Kernel	>= 5.11, < 5.15.209	—
Linux	Linux Kernel	>= 5.16, < 6.1.175	—
Linux	Linux Kernel	>= 6.2, < 6.6.140	—
Linux	Linux Kernel	>= 6.7, < 6.12.86	—
Linux	Linux Kernel	>= 6.13, < 6.18.27	—
Linux	Linux Kernel	>= 6.19, < 7.0.4	—
Linux	Linux Kernel	7.1	Rc1

References

Timeline

Published: May 27, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-46033?

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.

How severe is CVE-2026-46033?

CVE-2026-46033 has a CVSS score of 7.1/10 (HIGH severity). The EPSS model estimates a 0.13% probability of exploitation in the next 30 days.

How do I fix CVE-2026-46033?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.