Connection disruption via non-exact TCP reset
Published Aug 10, 2026 · Updated Aug 10, 2026
Improper TCP reset validation in Linux allows remote attackers to interrupt new connections with crafted RST packets during SYN-RECEIVED. The tcp_check_req() request-socket path accepts any in-window RST without requiring SEG.SEQ to equal RCV.NXT, so it removes the pending request instead of sending a challenge ACK. The packet must reach a TCP listener while the connection is half-open; successful delivery disrupts establishment of that connection without disclosing data.
Summary
What happened
Improper TCP reset validation in Linux allows remote attackers to interrupt new connections with crafted RST packets during SYN-RECEIVED. The tcp_check_req() request-socket path accepts any in-window RST without requiring SEG.SEQ to equal RCV.NXT, so it removes the pending request instead of sending a challenge ACK. The packet must reach a TCP listener while the connection is half-open; successful delivery disrupts establishment of that connection without disclosing data.
The record
- CVE
- CVE-2026-68118
- Published
- Aug 10, 2026
- Updated
- Aug 10, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-358, CWE-346, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 10, 2026CVE publishedPublication date reported by the CVE source.
- Aug 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=282f23c6ee343126156dd41218b22ece96d747e3 <22cec809b048495310f206d9abbcdbbfbdce3ae3
- Affected versionversion=282f23c6ee343126156dd41218b22ece96d747e3 <234f9ffbd9b2c1b24ec67200ea3cff07401bec48
- Affected versionversion=282f23c6ee343126156dd41218b22ece96d747e3 <a28c4fcbf774e23b4779cae468e3497a5ad1f4a1
- Affected versionversion=3.0.58 <3.1
- Affected versionversion=3.2.37 <3.3
- Affected versionversion=3.4.25 <3.5
- Affected versionversion=34fb350281ced2a72707a5c0064f69992d440edb
- Affected versionversion=3.6
- Affected versionversion=61f69dc4e40e41b0018f00fa4aeb23d3239556fb
- Affected versionversion=86791bbfe5ed7b275be040cfeff049a1624af1b7
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- SYN-RECEIVED RST packetdrill regression testproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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