CVE-2026-43190
netfilter: xt_tcpmss: check remaining length before reading optlen
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).
INFO
Published Date :
May 6, 2026, 12:16 p.m.
Last Modified :
May 6, 2026, 1:07 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to a patched version.
- Verify that netfilter: xt_tcpmss changes are applied.
- Review net/netfilter/xt_tcpmss.c for option length validation.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-43190.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-43190 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-43190
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-43190 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-43190 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 06, 2026
Action Type Old Value New Value Added 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). Added Reference https://git.kernel.org/stable/c/07a9b32eaae792ff7d0fcac14d8920c937c0a9c3 Added Reference https://git.kernel.org/stable/c/5e13d0a37666955b6cfddc0f73cb40ed645b8a05 Added Reference https://git.kernel.org/stable/c/735ee8582da3d239eb0c7a53adca61b79fb228b3 Added Reference https://git.kernel.org/stable/c/8b300f726640c48c3edfe9c453334dd801f4b74e Added Reference https://git.kernel.org/stable/c/cd5beda7e0e32865e214f28034bb92c1cecff885 Added Reference https://git.kernel.org/stable/c/eaedc0bc18be46fe7f58170e967959a932c4f824 Added Reference https://git.kernel.org/stable/c/f6c412dcfd76b0516d51aa847d8f4c7b70381b09 Added Reference https://git.kernel.org/stable/c/f895191dc32c53eaf443b6443fe40945b2f92287