netfilter: xt_tcpmss: check remaining length before reading optlen

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Summary

CVECVE-2026-43190
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-06 12:16:37 UTC
Updated2026-05-11 20:50:14 UTC
DescriptionIn 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).

Risk And Classification

Primary CVSS: v3.1 8.2 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

EPSS: 0.000680000 probability, percentile 0.208010000 (date 2026-05-12)

Problem Types: CWE-125

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary8.2HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
3.1CNADECLARED8.2HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 f895191dc32c53eaf443b6443fe40945b2f92287 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 cd5beda7e0e32865e214f28034bb92c1cecff885 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 eaedc0bc18be46fe7f58170e967959a932c4f824 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 07a9b32eaae792ff7d0fcac14d8920c937c0a9c3 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 8b300f726640c48c3edfe9c453334dd801f4b74e git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 5e13d0a37666955b6cfddc0f73cb40ed645b8a05 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 f6c412dcfd76b0516d51aa847d8f4c7b70381b09 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 735ee8582da3d239eb0c7a53adca61b79fb228b3 git Not specified
CNA Linux Linux affected 2.6.12 Not specified
CNA Linux Linux unaffected 2.6.12 semver Not specified
CNA Linux Linux unaffected 5.10.252 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.202 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.165 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.128 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.75 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.16 6.18.* semver Not specified
CNA Linux Linux unaffected 6.19.6 6.19.* semver Not specified
CNA Linux Linux unaffected 7.0 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/8b300f726640c48c3edfe9c453334dd801f4b74e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/eaedc0bc18be46fe7f58170e967959a932c4f824 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/07a9b32eaae792ff7d0fcac14d8920c937c0a9c3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/5e13d0a37666955b6cfddc0f73cb40ed645b8a05 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/f895191dc32c53eaf443b6443fe40945b2f92287 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/735ee8582da3d239eb0c7a53adca61b79fb228b3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/cd5beda7e0e32865e214f28034bb92c1cecff885 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/f6c412dcfd76b0516d51aa847d8f4c7b70381b09 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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