Out-of-bounds read in Linux kernel netfilter xt_tcpmss TCP option parser
CVE-2026-43190 is an out-of-bounds read in the Linux kernel's netfilter xt_tcpmss code, specifically in net/netfilter/xt_tcpmss.c. The TCP option parser reads op[i+1] without first validating that at least two bytes remain in the option buffer. If the final byte of the TCP option field is not an EOL (0) or NOP (1) option, the parser may attempt to access op[i+1] when i + 1 == optlen. This results in a read past the end of the TCP options area, potentially beyond the local stack buffer _opt or into the following packet payload. The issue was fixed by adding a remaining-length check before reading the option length byte.
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Impact
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Mitigation
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Exploits
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No public exploit code observed for this vulnerability.
Affected products & vendors
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
9 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.
No news coverage yet. Advisories and community discussion only.
The version that knows your environment.
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Every observed campaign linking this CVE to a named adversary.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.