In the Linux kernel, the following vulnerability has been resolved:
netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check
An unintended behavior in the TCP conntrack state machine allows a
connection to be forced into the CLOSE state using an RST packet with an
invalid sequence number.
Specifically, after a SYN packet is observed, an RST with an invalid SEQ
can transition the conntrack entry to TCP_CONNTRACK_CLOSE, regardless of
whether the RST corresponds to the expected reply direction. The relevant
code path assumes the RST is a response to an outgoing SYN, but does not
validate packet direction or ensure that a matching SYN was actually sent
in the opposite direction.
As a result, a crafted packet sequence consisting of a SYN followed by an
invalid-sequence RST can prematurely terminate an active NAT entry. This
makes connection teardown easier than intended.
So, tighten the state transition logic to ensure that RST-triggered
CLOSE transitions only occur when the RST is a valid response to a
previously observed SYN in the correct direction.
References
Configurations
Configuration 1 (hide)
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History
30 Oct 2026, 17:55
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://git.kernel.org/stable/c/2006979a15af5404bf932a325357683c0bac1656 - Patch | |
| References | () https://git.kernel.org/stable/c/2bb6d82b586ea5a4cb73bbdd6b7432e96096bc77 - Patch | |
| References | () https://git.kernel.org/stable/c/6476c17d536dbd321c073242e762ddb2713a1238 - Patch | |
| References | () https://git.kernel.org/stable/c/b98ab51c45c5608a1c19ce7fd17a3032469bb83f - Patch | |
| References | () https://git.kernel.org/stable/c/bed6e04be8e6b9133d8b16d5a42d0e0ce674fa9a - Patch | |
| References | () https://git.kernel.org/stable/c/d67c6adee8d1b65330d0174c4c367faba14e80a8 - Patch | |
| References | () https://git.kernel.org/stable/c/f206def4e86d810f927ba1d8e322ea72b29bce58 - Patch | |
| References | () https://git.kernel.org/stable/c/f5547bebc416d56f56fb5b86dc20aabfa42165a0 - Patch | |
| CPE | cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* |
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| First Time |
Linux linux Kernel
Linux |
19 Oct 2026, 21:17
| Type | Values Removed | Values Added |
|---|---|---|
| CWE | CWE-20 |
Information
Published : 2026-07-19 16:17
Updated : 2026-10-30 17:55
NVD link : CVE-2026-63913
Mitre link : CVE-2026-63913
CVE.ORG link : CVE-2026-63913
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-20
Improper Input Validation
