tcp: challenge ACK for non-exact RST in SYN-RECEIVED
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.
CVE-2026-68118
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-68118
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "282f23c6ee343126156dd41218b22ece96d747e3",
"lessThan": "8b0a3a094f4cae2fb92e4d08d4eef7246a9d9c49",
"versionType": "git"
},
{
"status": "affected",
"version": "282f23c6ee343126156dd41218b22ece96d747e3",
"lessThan": "0fe4636665d14a258de70b4f3e8248e6d42038f1",
"versionType": "git"
},
{
"status": "affected",
"version": "282f23c6ee343126156dd41218b22ece96d747e3",
"lessThan": "234f9ffbd9b2c1b24ec67200ea3cff07401bec48",
"versionType": "git"
},
{
"status": "affected",
"version": "282f23c6ee343126156dd41218b22ece96d747e3",
"lessThan": "22cec809b048495310f206d9abbcdbbfbdce3ae3",
"versionType": "git"
},
{
"status": "affected",
"version": "282f23c6ee343126156dd41218b22ece96d747e3",
"lessThan": "a28c4fcbf774e23b4779cae468e3497a5ad1f4a1",
"versionType": "git"
},
{
"status": "affected",
"version": "86791bbfe5ed7b275be040cfeff049a1624af1b7",
"versionType": "git"
},
{
"status": "affected",
"version": "61f69dc4e40e41b0018f00fa4aeb23d3239556fb",
"versionType": "git"
},
{
"status": "affected",
"version": "34fb350281ced2a72707a5c0064f69992d440edb",
"versionType": "git"
},
{
"status": "affected",
"version": "3.0.58",
"lessThan": "3.1",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.2.37",
"lessThan": "3.3",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.4.25",
"lessThan": "3.5",
"versionType": "semver"
}
],
"programFiles": [
"include/net/tcp.h",
"net/ipv4/tcp_input.c",
"net/ipv4/tcp_minisocks.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.6"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.6",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.153",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.105",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"include/net/tcp.h",
"net/ipv4/tcp_input.c",
"net/ipv4/tcp_minisocks.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-68118
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #41122 · Revision 1
- Added to Heist Feed
- Publisher date