CVE-2026-43198
Published: May 7, 2026Last modified: June 24, 2026
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 9.8 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | HIGH |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Vulnerable (6.1.170-r0) |
| 25 LTS | linux-lts | Vulnerable (6.12.85-r0) | |
| Stream | linux-lts | Fixed (6.18.35-r1) |
References
- 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/security/cve/CVE-2026-43198
- https://bugzilla.redhat.com/show_bug.cgi?id=2467228
- https://git.kernel.org/stable/c/7178e2a8027423b2af17ab95df73a749a5b72e5b
- https://git.kernel.org/stable/c/858d2a4f67ff69e645a43487ef7ea7f28f06deae
- https://git.kernel.org/stable/c/fe89b2f05b854847784f91127319172945c1fadd
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43198.json