CVE-2026-63913

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.
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
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:7.1:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*

History

30 Oct 2026, 17:55

Type Values Removed Values Added
References () https://git.kernel.org/stable/c/2006979a15af5404bf932a325357683c0bac1656 - () https://git.kernel.org/stable/c/2006979a15af5404bf932a325357683c0bac1656 - Patch
References () https://git.kernel.org/stable/c/2bb6d82b586ea5a4cb73bbdd6b7432e96096bc77 - () https://git.kernel.org/stable/c/2bb6d82b586ea5a4cb73bbdd6b7432e96096bc77 - Patch
References () https://git.kernel.org/stable/c/6476c17d536dbd321c073242e762ddb2713a1238 - () https://git.kernel.org/stable/c/6476c17d536dbd321c073242e762ddb2713a1238 - Patch
References () https://git.kernel.org/stable/c/b98ab51c45c5608a1c19ce7fd17a3032469bb83f - () https://git.kernel.org/stable/c/b98ab51c45c5608a1c19ce7fd17a3032469bb83f - Patch
References () https://git.kernel.org/stable/c/bed6e04be8e6b9133d8b16d5a42d0e0ce674fa9a - () https://git.kernel.org/stable/c/bed6e04be8e6b9133d8b16d5a42d0e0ce674fa9a - Patch
References () https://git.kernel.org/stable/c/d67c6adee8d1b65330d0174c4c367faba14e80a8 - () https://git.kernel.org/stable/c/d67c6adee8d1b65330d0174c4c367faba14e80a8 - Patch
References () https://git.kernel.org/stable/c/f206def4e86d810f927ba1d8e322ea72b29bce58 - () https://git.kernel.org/stable/c/f206def4e86d810f927ba1d8e322ea72b29bce58 - Patch
References () https://git.kernel.org/stable/c/f5547bebc416d56f56fb5b86dc20aabfa42165a0 - () 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:*:*:*:*:*:*
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