CVE-2026-68118

Last refreshed2026-10-17

Status: UPDATED | Advisory ID: CVE-2026-68118

Key Details

CVE	CVE-2026-68118
CVSS Score / Version	8.2 (High) / CVSS v3.1
Updated	2026-10-16
CVSS Vector	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H`
CVSS Prose	attack vector is network; attack complexity is low; privileges required is none; user interaction is none; scope is unchanged; confidentiality impact is none; integrity impact is low; availability impact is high.
Affected products	Linux Kernel

Vendor	Product	Affected Versions	Patch Status
Linux	Linux Kernel

Vendor

Product

Affected Versions

Patch Status

Linux

Linux Kernel

Subsystems	OT Supporting Infrastructure
Sectors	All Sectors

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. (NVD)

Monitor Linux's web page for any future patch releases.

Source	Reference
NVD	https://nvd.nist.gov/vuln/detail/CVE-2026-68118
CVE	https://www.cve.org/CVERecord?id=CVE-2026-68118

Source

Reference

NVD

CVE