CVE-2026-43033

Kernel memory corruption via misplaced sequence bits

Published May 1, 2026 · Updated May 1, 2026

Out-of-bounds write in Linux Kernel 4.3 and later allows local users to corrupt kernel memory through AF_ALG authencesn decryption. In crypto/authencesn.c, the out-of-place decrypt path places four high-order sequence bytes at the end of the destination buffer before authentication and hashes a misarranged buffer. A local low-privileged process can reach the branch through AF_ALG sockets without a valid tag; ordinary inbound ESP uses in-place buffers and does not directly reach it.

CVSS severity7.8
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Linux Kernel 4.3 and later allows local users to corrupt kernel memory through AF_ALG authencesn decryption. In crypto/authencesn.c, the out-of-place decrypt path places four high-order sequence bytes at the end of the destination buffer before authentication and hashes a misarranged buffer. A local low-privileged process can reach the branch through AF_ALG sockets without a valid tag; ordinary inbound ESP uses in-place buffers and does not directly reach it.

The record

CVE
CVE-2026-43033
Published
May 1, 2026
Updated
May 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 1, 2026CVE publishedPublication date reported by the CVE source.
  2. May 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=104880a6b470958ddc30e139c41aa4f6ed3a5234 <153d5520c3f9fd62e71c7e7f9e34b59cf411e555
  2. Affected versionversion=104880a6b470958ddc30e139c41aa4f6ed3a5234 <5466e7d0cd9e4f9cef9d8f18f18b60e7bc1c77e5
  3. Affected versionversion=104880a6b470958ddc30e139c41aa4f6ed3a5234 <89fe118b6470119b20c04afc36e45b81a69ea11f
  4. Affected versionversion=104880a6b470958ddc30e139c41aa4f6ed3a5234 <8c62f618576519dbed6816fafc623ce592953025
  5. Affected versionversion=104880a6b470958ddc30e139c41aa4f6ed3a5234 <cded4002d22177e8deaca1f257ecd932c9582b6b
  6. Affected versionversion=104880a6b470958ddc30e139c41aa4f6ed3a5234 <d0c4ff6812386880f30bc64c2921299cc4d7b47f
  7. Affected versionversion=104880a6b470958ddc30e139c41aa4f6ed3a5234 <d589abd8b019b07075fda255ceab8c8e950cdb3f
  8. Affected versionversion=104880a6b470958ddc30e139c41aa4f6ed3a5234 <e02494114ebf7c8b42777c6cd6982f113bfdbec7
  9. Affected versionversion=4.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=104880a6b470958ddc30e139c41aa4f6ed3a5234 <153d5520c3f9fd62e71c7e7f9e34b59cf411e555; version=104880a6b470958ddc30e139c41aa4f6ed3a5234 <5466e7d0cd9e4f9cef9d8f18f18b60e7bc1c77e5; version=104880a6b470958ddc30e139c41aa4f6ed3a5234 <89fe118b6470119b20c04afc36e45b81a69ea11f; version=104880a6b470958ddc30e139c41aa4f6ed3a5234 <8c62f618576519dbed6816fafc623ce592953025; version=104880a6b470958ddc30e139c41aa4f6ed3a5234 <cded4002d22177e8deaca1f257ecd932c9582b6b; version=104880a6b470958ddc30e139c41aa4f6ed3a5234 <d0c4ff6812386880f30bc64c2921299cc4d7b47f; version=104880a6b470958ddc30e139c41aa4f6ed3a5234 <d589abd8b019b07075fda255ceab8c8e950cdb3f; version=104880a6b470958ddc30e139c41aa4f6ed3a5234 <e02494114ebf7c8b42777c6cd6982f113bfdbec7; version=4.3

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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