CVE-2026-46033 crypto: authencesn - reject short ahash digests during instance creation
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.
CVSS 3.1 detail
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:HExploitable with local access to the machine, with an ordinary account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- Interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- High
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux 7.1 | earliest → < 7.1 | 7.1 |
| Linux 7.0 | earliest → < 7.0.4 | 7.0.4 |
| Linux 6.18 | earliest → < 6.18.27 | 6.18.27 |
| Linux 6.12 | earliest → < 6.12.86 | 6.12.86 |
| Linux 6.6 | earliest → < 6.6.140 | 6.6.140 |
| Linux 6.1 | earliest → < 6.1.175 | 6.1.175 |
| Linux 5.15 | earliest → < 5.15.209 | 5.15.209 |
| Linux 5.10 | earliest → < 5.10.258 | 5.10.258 |
| Linux | 4.11 | No fix stated |
Show the 9 other branches Hide the 9 other branches
| Product | Affected versions | Fixed in |
|---|---|---|
| Red Hat Enterprise Linux 10 | Versions not published | |
| Red Hat Enterprise Linux 8 | Versions not published | |
| Red Hat Enterprise Linux 9 | Versions not published | |
| Red Hat Enterprise Linux 6 | Versions not published | |
| Red Hat Enterprise Linux 7 | Versions not published | |
| SIMATIC S7-1500 CPU 1518-4 PN/DP MFP 3.1 | 3.1.7 → latest | No fix stated |
| SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP 3.1 | 3.1.7 → latest | No fix stated |
| SIPLUS S7-1500 CPU 1518-4 PN/DP MFP 3.1 | 3.1.7 → latest | No fix stated |
| SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | Versions not published |