CVE-2026-43198
Vulnerability Summary
Timeline
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 Metrics
- v4.0•HIGH•Score: 8.2CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- v3.1•CRITICAL•Score: 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Trends
Current EPSS score: 0.30%• Percentile: 23%
Techniques & Countermeasures
- CWE-362•Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
- CWE-821•Incorrect Synchronization
The product utilizes a shared resource in a concurrent manner, but it does not correctly synchronize access to the resource.
Affected Systems
- chainguard•linux-aws-6.12
all
- chainguard•linux-azure-6.12
all
- chainguard•linux-gcp-6.12
all
- chainguard•linux-qemu-6.12
all
- chainguard•linux-vmware-6.12
all
- debian•linux
all | all | all | < 6.19.6-1
- ubuntu•linux
all | < 3.13.0-215.266 | < 4.4.0-284.318 | < 4.15.0-254.266 | < 5.4.0-234.254 | < 5.15.0-187.197 | < 6.8.0-137.137 | all
- ubuntu•linux-allwinner-5.19
all
- ubuntu•linux-aws
all | < 4.4.0-1157.163 | < 4.4.0-1195.210 | < 4.15.0-1195.208 | < 5.4.0-1162.173 | < 5.15.0-1113.120 | < 6.8.0-1062.65 | all
- ubuntu•linux-aws-5.0
all
- ubuntu•linux-aws-5.11
all
- ubuntu•linux-aws-5.13
all
- ubuntu•linux-aws-5.15
all | < 5.15.0-1114.121~20.04.1
- ubuntu•linux-aws-5.19
all
- ubuntu•linux-aws-5.3
all
- ubuntu•linux-aws-5.4
all | < 5.4.0-1162.173~18.04.1
- ubuntu•linux-aws-5.8
all
- ubuntu•linux-aws-6.14
all
- ubuntu•linux-aws-6.17
all
- ubuntu•linux-aws-6.2
all
- ubuntu•linux-aws-6.5
all
- ubuntu•linux-aws-6.8
all | < 6.8.0-1062.65~22.04.2
- ubuntu•linux-aws-fips
< 4.15.0-2133.139 | all | < 5.4.0-1163.174+fips1 | < 5.15.0-1113.120+fips1 | < 6.8.0-1062.65+fips1
- ubuntu•linux-aws-hwe
all | < 4.15.0-1195.208~16.04.1
- ubuntu•linux-azure
all | < 4.15.0-1205.220~14.04.1 | < 4.15.0-1205.220~16.04.1 | all | < 5.4.0-1167.173 | < 5.15.0-1118.127 | < 6.8.0-1064.72 | all
- ubuntu•linux-azure-4.15
< 4.15.0-1205.220
- ubuntu•linux-azure-5.11
all
- ubuntu•linux-azure-5.13
all
- ubuntu•linux-azure-5.15
all | < 5.15.0-1119.128~20.04.1
- ubuntu•linux-azure-5.19
all
- ubuntu•linux-azure-5.3
all
- ubuntu•linux-azure-5.4
all | < 5.4.0-1167.173~18.04.1
- ubuntu•linux-azure-5.8
all
- ubuntu•linux-azure-6.11
all
- ubuntu•linux-azure-6.14
all
- ubuntu•linux-azure-6.17
< 6.17.0-1022.22
- ubuntu•linux-azure-6.2
all
- ubuntu•linux-azure-6.5
all
- ubuntu•linux-azure-6.8
< 6.8.0-1064.72~22.04.1
- ubuntu•linux-azure-edge
all
- ubuntu•linux-azure-fde
all | < 5.15.0-1118.127 | < 6.8.0-1063.70 | all | all
- ubuntu•linux-azure-fde-5.15
all | < 5.15.0-1118.127~20.04.1
- ubuntu•linux-azure-fde-5.19
all
- ubuntu•linux-azure-fde-6.14
all
- ubuntu•linux-azure-fde-6.17
all
- ubuntu•linux-azure-fde-6.2
all
- ubuntu•linux-azure-fde-6.8
< 6.8.0-1063.70~22.04.1
- ubuntu•linux-azure-fde-7.0
all
- ubuntu•linux-azure-fips
< 4.15.0-2113.119 | all | < 5.4.0-1167.173+fips1 | < 5.15.0-1118.127+fips1 | < 6.8.0-1064.72+fips1
- ubuntu•linux-azure-nvidia
all
Showing first 50 affected entries in server-rendered view.
References (62)
- https://git.kernel.org/stable/c/7178e2a8027423b2af17ab95df73a749a5b72e5b
- https://git.kernel.org/stable/c/858d2a4f67ff69e645a43487ef7ea7f28f06deae
- https://git.kernel.org/stable/c/fe89b2f05b854847784f91127319172945c1fadd
- 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
- https://access.redhat.com/errata/RHSA-2026:33215
- https://access.redhat.com/errata/RHSA-2026:30129
- https://access.redhat.com/errata/RHSA-2026:33285
- https://access.redhat.com/errata/RHSA-2026:36216
- https://access.redhat.com/errata/RHSA-2026:36073
- https://access.redhat.com/errata/RHSA-2026:34443
- https://access.redhat.com/errata/RHSA-2026:34094
- https://access.redhat.com/errata/RHSA-2026:36349
- https://access.redhat.com/errata/RHSA-2026:35896
- https://access.redhat.com/errata/RHSA-2026:35894
- https://access.redhat.com/errata/RHSA-2026:35863
- https://access.redhat.com/errata/RHSA-2026:36348
- https://access.redhat.com/errata/RHSA-2026:35904
- https://access.redhat.com/errata/RHSA-2026:41236
- https://ubuntu.com/security/CVE-2026-43198
- https://www.cve.org/CVERecord?id=CVE-2026-43198
- https://git.kernel.org/linus/858d2a4f67ff69e645a43487ef7ea7f28f06deae
- https://ubuntu.com/security/notices/USN-8630-1
- https://ubuntu.com/security/notices/USN-8631-1
- https://ubuntu.com/security/notices/USN-8633-1
- https://ubuntu.com/security/notices/USN-8634-1
- https://ubuntu.com/security/notices/USN-8635-1
- https://ubuntu.com/security/notices/USN-8636-1
- https://security-tracker.debian.org/tracker/CVE-2026-43198
- https://ubuntu.com/security/notices/USN-8630-2
- https://ubuntu.com/security/notices/USN-8631-2
- https://ubuntu.com/security/notices/USN-8631-3
- https://ubuntu.com/security/notices/USN-8633-2
- https://ubuntu.com/security/notices/USN-8631-4
- https://ubuntu.com/security/notices/USN-8645-1
- https://ubuntu.com/security/notices/USN-8630-3
- https://ubuntu.com/security/notices/USN-8636-2
- https://ubuntu.com/security/notices/USN-8656-1
- https://ubuntu.com/security/notices/USN-8661-1
- https://ubuntu.com/security/notices/USN-8630-4
- https://ubuntu.com/security/notices/USN-8662-1
- https://ubuntu.com/security/notices/USN-8666-1
- https://ubuntu.com/security/notices/USN-8662-2
- https://ubuntu.com/security/notices/USN-8667-1
- https://ubuntu.com/security/notices/USN-8669-1
- https://ubuntu.com/security/notices/USN-8661-2
- https://ubuntu.com/security/notices/USN-8630-5
- https://ubuntu.com/security/notices/USN-8666-2
- https://ubuntu.com/security/notices/USN-8661-3
- https://ubuntu.com/security/notices/USN-8666-3
- https://ubuntu.com/security/notices/USN-8661-4
- https://ubuntu.com/security/notices/USN-8715-1
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43198.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-43198
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- 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://ubuntu.com/security/notices/USN-8715-2