CVE-2026-43190

Summary

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).

Affected Software

VendorProductVersion RangeStatus
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < f895191dc32c53eaf443b6443fe40945b2f92287affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < cd5beda7e0e32865e214f28034bb92c1cecff885affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < eaedc0bc18be46fe7f58170e967959a932c4f824affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 07a9b32eaae792ff7d0fcac14d8920c937c0a9c3affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 8b300f726640c48c3edfe9c453334dd801f4b74eaffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 5e13d0a37666955b6cfddc0f73cb40ed645b8a05affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < f6c412dcfd76b0516d51aa847d8f4c7b70381b09affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 735ee8582da3d239eb0c7a53adca61b79fb228b3affected
LinuxLinux2.6.12affected
LinuxLinux0 < 2.6.12unaffected
LinuxLinux5.10.252 <= 5.10.*unaffected
LinuxLinux5.15.202 <= 5.15.*unaffected
LinuxLinux6.1.165 <= 6.1.*unaffected
LinuxLinux6.6.128 <= 6.6.*unaffected
LinuxLinux6.12.75 <= 6.12.*unaffected
LinuxLinux6.18.16 <= 6.18.*unaffected
LinuxLinux6.19.6 <= 6.19.*unaffected
LinuxLinux7.0 <= *unaffected

Weaknesses

References