🛡️ CVE-2026-43190 — kernel

🟠 CVSS 8.2 — High ✅ No Known Exploit NVD
8.2
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

netfilter: xt_tcpmss: check remaining length before reading optlen

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).

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity none, availability high.

Affected software

CVE-2026-43190 is recorded against 3 packages.

  • kernel (from 6.19.0 up to 6.19.6)
  • linux-kernel
  • unknown

Timeline and source

Published on 6 May 2026 and last revised on 6 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

CVE-2026-43190 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity High
CVSS Score 8.2
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2026-05-06
Updated 2026-08-12
Modified 2026-08-06

Affected Packages

Software From version Fixed in
kernel 6.19.0 6.19.6
linux-kernel — —
unknown — —

References

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