CyberSecBulletin
CVE-2026-43190NVD status: Modified

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2026-43190 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 8.2 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions f895191dc32c53eaf443b6443fe40945b2f92287, cd5beda7e0e32865e214f28034bb92c1cecff885, eaedc0bc18be46fe7f58170e967959a932c4f824 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.46% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to f895191dc32c53eaf443b6443fe40945b2f92287 or cd5beda7e0e32865e214f28034bb92c1cecff885 or eaedc0bc18be46fe7f58170e967959a932c4f824 or 07a9b32eaae792ff7d0fcac14d8920c937c0a9c3, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.252 or 5.15.202 or 6.1.165 or 6.6.128, whichever matches your release line, or a later version.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, f895191dc32c53eaf443b6443fe40945b2f92287; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, cd5beda7e0e32865e214f28034bb92c1cecff885; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, eaedc0bc18be46fe7f58170e967959a932c4f824; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 07a9b32eaae792ff7d0fcac14d8920c937c0a9c3; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 8b300f726640c48c3edfe9c453334dd801f4b74e; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 5e13d0a37666955b6cfddc0f73cb40ed645b8a05; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, f6c412dcfd76b0516d51aa847d8f4c7b70381b09; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 735ee8582da3d239eb0c7a53adca61b79fb228b3; and 1 more rangesf895191dc32c53eaf443b6443fe40945b2f92287, cd5beda7e0e32865e214f28034bb92c1cecff885, eaedc0bc18be46fe7f58170e967959a932c4f824, 07a9b32eaae792ff7d0fcac14d8920c937c0a9c3, 8b300f726640c48c3edfe9c453334dd801f4b74e, 5e13d0a37666955b6cfddc0f73cb40ed645b8a05
LinuxLinux Kernel2.6.12.1 up to, but not including, 5.10.252; 5.11 up to, but not including, 5.15.202; 5.16 up to, but not including, 6.1.165; 6.2 up to, but not including, 6.6.128; 6.7 up to, but not including, 6.12.75; 6.13 up to, but not including, 6.18.16; 6.19 up to, but not including, 6.19.6; 2.6.125.10.252, 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.16

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
LowSome restricted data can be read.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_tcpmss: check remaining length before reading optlen Quoting reporter: In net/netfilter/xt_tcpmss.c (lines 53-68), the TCP option parser reads op[i+1] directly without validating the remaining option length. If the last byte of the option field is not EOL/NOP (0/1), the code attempts to index op[i+1]. In the case where i + 1 == optlen, this causes an out-of-bounds read, accessing memory past the optlen boundary (either reading beyond the stack buffer _opt or the following payload).

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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