AUGUST 16, 2026
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Case File

CVE-2026-68118

HIGH · CVSS 8.2 EPSS 0.38%

Source: NVD + CISA KEV + EPSS · Published 2026-08-10 · Last synced 2026-08-16

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's TCP implementation, specifically in the handling of RST packets during the SYN-RECEIVED state, which could allow an attacker to disrupt connections by sending non-exact RST packets. This flaw can lead to improper connection termination, potentially enabling denial-of-service conditions. Organizations using Linux systems, particularly those relying on TCP for critical services, should prioritize applying the relevant patches to mitigate this risk.

CVE
CVE-2026-68118
Severity
HIGH
CVSS
8.2
EPSS
0.38%
Linux

Original NVD Description

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.