CVE-2026-43190

netfilter: xt_tcpmss: check remaining length before reading optlen

State
Published
Severity
8.2 High
Published
May 6, 2026
Updated
Oct 19, 2026
Reserved
May 1, 2026

Read the record on cve.org

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).

Scores

CVSSScoreVectorSource
3.18.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:HLinux

Weaknesses

Affected Products

ProductVersions
LinuxLinux
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before f895191dc32c53eaf443b6443fe40945b2f92287Affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before cd5beda7e0e32865e214f28034bb92c1cecff885Affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before eaedc0bc18be46fe7f58170e967959a932c4f824Affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 07a9b32eaae792ff7d0fcac14d8920c937c0a9c3Affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 8b300f726640c48c3edfe9c453334dd801f4b74eAffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 5e13d0a37666955b6cfddc0f73cb40ed645b8a05Affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before f6c412dcfd76b0516d51aa847d8f4c7b70381b09Affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 735ee8582da3d239eb0c7a53adca61b79fb228b3Affected
LinuxLinux
  • 2.6.12Affected
  • before 2.6.12Not affected
  • 5.10.252 through 5.10.*Not affected
  • 5.15.202 through 5.15.*Not affected
  • 6.1.165 through 6.1.*Not affected
  • 6.6.128 through 6.6.*Not affected
  • 6.12.75 through 6.12.*Not affected
  • 6.18.16 through 6.18.*Not affected
  • 6.19.6 through 6.19.*Not affected
  • 7.0 and laterNot affected

References

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