Critical 9.8Published May 6, 2026

CVE-2026-43198tcp: fix potential race in tcp_v6_syn_recv_sock()

Updated under an hour ago (Oct 28, 2026, 5:30 AM ET)

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It affects Linux and 10 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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: 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-821, CWE-362
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before aef4a9ae95d1bc4f7897065011e6261026719aeb; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before dad1fe7db6c6519138430ac8f5e589c18f83bfc9; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before a7e761ba55efaa9c49e0afdd304bb78167af3429; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before cd644e6dc72eec8d9d988717ea1c54f8668ded69; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 9ed654e340f4c73bc6f0af2fbc90ac293e645ce0; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before fe89b2f05b854847784f91127319172945c1fadd; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 7178e2a8027423b2af17ab95df73a749a5b72e5b; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 858d2a4f67ff69e645a43487ef7ea7f28f06deae	CNA record
Red Hat Red Hat Enterprise Linux 10 redhat:enterprise_linux	from 0:6.12.0-211.28.1.el10_2 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support redhat:enterprise_linux_eus	from 0:6.12.0-55.84.1.el10_0 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support redhat:rhel_extras_rt_els	from 0:3.10.0-1160.155.1.rt56.1307.el7 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support redhat:rhel_els	from 0:3.10.0-1160.155.1.el7 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support redhat:rhel_aus	from 0:4.18.0-305.197.1.el8_4 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On redhat:rhel_eus_long_life	from 0:4.18.0-305.197.1.el8_4 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service redhat:rhel_tus	from 0:4.18.0-477.150.1.el8_8 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions redhat:rhel_e4s	from 0:4.18.0-477.150.1.el8_8 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support redhat:rhel_eus	from 0:5.14.0-570.125.1.el9_6 not affected	CISA ADP
1–10 of 11

References

References

https://git.kernel.org/stable/c/aef4a9ae95d1bc4f7897065011e6261026719aeb
https://git.kernel.org/stable/c/dad1fe7db6c6519138430ac8f5e589c18f83bfc9
https://git.kernel.org/stable/c/a7e761ba55efaa9c49e0afdd304bb78167af3429
https://git.kernel.org/stable/c/cd644e6dc72eec8d9d988717ea1c54f8668ded69
https://git.kernel.org/stable/c/9ed654e340f4c73bc6f0af2fbc90ac293e645ce0
https://git.kernel.org/stable/c/fe89b2f05b854847784f91127319172945c1fadd	patch
https://git.kernel.org/stable/c/7178e2a8027423b2af17ab95df73a749a5b72e5b	patch
https://git.kernel.org/stable/c/858d2a4f67ff69e645a43487ef7ea7f28f06deae	patch
https://access.redhat.com/errata/RHSA-2026:30129
https://access.redhat.com/errata/RHSA-2026:33215
1–10 of 25

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.