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Vulnerability record · CVE-2026-43198 · published 6 May 2026

CVE-2026-43198: Linux kernel race condition vulnerability

Linux · Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: tcp: fix potential race in tcp_v6_syn_recv_sock() Code in tcp_v6_syn_recv_sock() after the call to tcp_v4_syn_recv_sock() is done too late. After tcp_v4_syn_recv_sock(), the child socket is already visible from TCP ehash table and other cpus might use it. Since newinet->pinet6 is still pointing to the listener ipv6_pinfo bad things can happen as syzbot found. Move the problematic code in tcp_v6_mapped_child_init() and call this new helper from tcp_v4_syn_recv_sock() before the ehash insertion. This allows the removal of one tcp_sync_mss(), since tcp_v4_syn_recv_sock() will call it with the correct context.

9.8 CVSS 3.1 Critical EPSS 0.40% · top 69.0% CWE-362 · Race conditionCWE-821 · CWE-821
9.8CVSS 3.1 base score
0.40%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
25References
14 Sep 2026Last modified by NVD

Description

In the Linux kernel, the following vulnerability has been resolved: tcp: fix potential race in tcp_v6_syn_recv_sock() Code in tcp_v6_syn_recv_sock() after the call to tcp_v4_syn_recv_sock() is done too late. After tcp_v4_syn_recv_sock(), the child socket is already visible from TCP ehash table and other cpus might use it. Since newinet->pinet6 is still pointing to the listener ipv6_pinfo bad things can happen as syzbot found. Move the problematic code in tcp_v6_mapped_child_init() and call this new helper from tcp_v4_syn_recv_sock() before the ehash insertion. This allows the removal of one tcp_sync_mss(), since tcp_v4_syn_recv_sock() will call it with the correct context.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://git.kernel.org/stable/c/7178e2a8027423b2af17ab95df73a749a5b72e5b Patch
https://git.kernel.org/stable/c/858d2a4f67ff69e645a43487ef7ea7f28f06deae Patch
https://git.kernel.org/stable/c/9ed654e340f4c73bc6f0af2fbc90ac293e645ce0
https://git.kernel.org/stable/c/a7e761ba55efaa9c49e0afdd304bb78167af3429
https://git.kernel.org/stable/c/aef4a9ae95d1bc4f7897065011e6261026719aeb
https://git.kernel.org/stable/c/cd644e6dc72eec8d9d988717ea1c54f8668ded69
https://git.kernel.org/stable/c/dad1fe7db6c6519138430ac8f5e589c18f83bfc9
https://git.kernel.org/stable/c/fe89b2f05b854847784f91127319172945c1fadd Patch
https://access.redhat.com/errata/RHSA-2026:30129
https://access.redhat.com/errata/RHSA-2026:33215
https://access.redhat.com/errata/RHSA-2026:33285
https://access.redhat.com/errata/RHSA-2026:34094
https://access.redhat.com/errata/RHSA-2026:34443
https://access.redhat.com/errata/RHSA-2026:35863
https://access.redhat.com/errata/RHSA-2026:35894
https://access.redhat.com/errata/RHSA-2026:35896
https://access.redhat.com/errata/RHSA-2026:35904
https://access.redhat.com/errata/RHSA-2026:36073
https://access.redhat.com/errata/RHSA-2026:36216
https://access.redhat.com/errata/RHSA-2026:36348
https://access.redhat.com/errata/RHSA-2026:36349
https://access.redhat.com/errata/RHSA-2026:41236
https://access.redhat.com/security/cve/CVE-2026-43198
https://bugzilla.redhat.com/show_bug.cgi?id=2467228
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43198.json

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Source: NIST National Vulnerability Database (record CVE-2026-43198), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.