Out-of-bounds Read in Linux

CVE-2026-43190

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).

Vulnerability class: Buffer Overflow

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H.

EPSS exploit prediction

EPSS: 0.006 (48.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-43190: held from 0.005 to 0.006.

EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.002

Affected products

  • Linux — versions 6.1.165, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 7.0
  • Linux Kernel — versions 2.6.12

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-43190?
CVE-2026-43190 is a high-severity vulnerability in Linux, classified under Out-of-bounds Read. CVSS score: 8.2/10. Published 2026-05-06.
How severe is CVE-2026-43190?
High severity. CVSS v3 base score is 8.2 out of 10.