Critical severity · published May 8, 2026
CVE-2026-43383
net/tcp-md5: Fix MAC comparison to be constant-time
9.4
CVSS
0.5%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved:
net/tcp-md5: Fix MAC comparison to be constant-time
To prevent timing attacks, MACs need to be compared in constant
time. Use the appropriate helper function for this.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 45% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
2.6.20 before 5.10.253; 5.11 before 6.1.167; 6.2 before 6.6.130; 6.7 before 6.12.78; 6.13 before 6.18.19; 6.19 before 6.19.9; +2 more · source: NVD
LI
Linux · Linux
cfb6eeb4c860592edd123fdea908d23c6ad1c7dc before 821c8751fdeecdeecabeb11704dd33439c9e4bbc; cfb6eeb4c860592edd123fdea908d23c6ad1c7dc before ff44ec94d4fc8348600a69de0a8fa1102c23bce8; cfb6eeb4c860592edd123fdea908d23c6ad1c7dc before 345a9530756528d7ca407663d659c3c40e75c3dd; cfb6eeb4c860592edd123fdea908d23c6ad1c7dc before 5d305a95130a8d08b9545e47f1e18d29d59866cb; cfb6eeb4c860592edd123fdea908d23c6ad1c7dc before 02669e2a4d207068edce7e8b5fafd85822018ce6; cfb6eeb4c860592edd123fdea908d23c6ad1c7dc before ae3831b44f477de048287493e184fc3ff913b624; +3 more · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-43383
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-43383
Patch
https://git.kernel.org/stable/c/02669e2a4d207068edce7e8b5fafd85822018ce6
Patch
https://git.kernel.org/stable/c/345a9530756528d7ca407663d659c3c40e75c3dd
Patch
https://git.kernel.org/stable/c/46d0d6f50dab706637f4c18a470aac20a21900d3
Patch
https://git.kernel.org/stable/c/5d305a95130a8d08b9545e47f1e18d29d59866cb
Patch
https://git.kernel.org/stable/c/821c8751fdeecdeecabeb11704dd33439c9e4bbc
Patch
https://git.kernel.org/stable/c/ae3831b44f477de048287493e184fc3ff913b624
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