CVE-2026-68118

CVE CVE-2026-68118EUVD EUVD-2026-55499Published 2026-08-10T11:58:38.000Z

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: tcp: challenge ACK for non-exact RST in SYN-RECEIVED The SYN-RECEIVED request-socket path in tcp_check_req() accepts an in-window RST without requiring SEG.SEQ to exactly match RCV.NXT. A non-exact RST therefore removes the request instead of eliciting a challenge ACK. RFC 9293 section 3.10.7.4 applies the RFC 5961 reset check in SYN-RECEIVED: an exact RST resets the connection, while a non-exact in-window RST must trigger a challenge ACK and be dropped. Apply that check before the ACK-field validation, following the RFC sequence-number, RST, then ACK processing order. Factor the per-netns challenge ACK quota out of tcp_send_challenge_ack() so request sockets can share it. Use the request socket's send_ack() callback and its own out-of-window ACK timestamp to send and rate-limit the response.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

Linux — Linux 3.0.58 <3.1; 282f23c6ee343126156dd41218b22ece96d747e3 <234f9ffbd9b2c1b24ec67200ea3cff07401bec48; 3.4.25 <3.5; 3.2.37 <3.3; 34fb350281ced2a72707a5c0064f69992d440edb; 282f23c6ee343126156dd41218b22ece96d747e3 <a28c4fcbf774e23b4779cae468e3497a5ad1f4a1; patch: 7.2-rc5; patch: 7.1.6; 61f69dc4e40e41b0018f00fa4aeb23d3239556fb; 3.6; 282f23c6ee343126156dd41218b22ece96d747e3 <22cec809b048495310f206d9abbcdbbfbdce3ae3; patch: 6.18.42; 86791bbfe5ed7b275be040cfeff049a1624af1b7; patch: 0

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

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Linux — Linux

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