Answer in brief
CVE-2026-43190 records a High severity (CVSS 8.2) vulnerability in netfilter: xt_tcpmss: check remaining length before reading optlen. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:2.6.12:rc6:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f895191dc32c53eaf443b6443fe40945b2f92287 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <cd5beda7e0e32865e214f28034bb92c1cecff885 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <eaedc0bc18be46fe7f58170e967959a932c4f824 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <07a9b32eaae792ff7d0fcac14d8920c937c0a9c3 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8b300f726640c48c3edfe9c453334dd801f4b74e || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5e13d0a37666955b6cfddc0f73cb40ed645b8a05 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f6c412dcfd76b0516d51aa847d8f4c7b70381b09 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <735ee8582da3d239eb0c7a53adca61b79fb228b3 | f895191dc32c53eaf443b6443fe40945b2f92287, cd5beda7e0e32865e214f28034bb92c1cecff885, eaedc0bc18be46fe7f58170e967959a932c4f824, 07a9b32eaae792ff7d0fcac14d8920c937c0a9c3, 8b300f726640c48c3edfe9c453334dd801f4b74e, 5e13d0a37666955b6cfddc0f73cb40ed645b8a05, f6c412dcfd76b0516d51aa847d8f4c7b70381b09, 735ee8582da3d239eb0c7a53adca61b79fb228b3 |
| Linux/Linuxgeneric | 2.6.12 | Not reported |
Published upstream
May 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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).
Quoted source text, attributed separately from HOL analysis.