Riskcovery

CVE-2026-43198

tcp: fix potential race in tcp_v6_syn_recv_sock()

State
Published
Severity
9.8 Critical
Published
May 6, 2026
Updated
Oct 19, 2026
Reserved
May 1, 2026

Read the record on cve.org

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.

Scores

CVSSScoreVectorSource
3.19.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HLinux
3.17.0 HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:Hredhat-SADP

Weaknesses

  • CWE-821 Incorrect Synchronization
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Affected Products

ProductVersions
LinuxLinux
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before aef4a9ae95d1bc4f7897065011e6261026719aebAffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before dad1fe7db6c6519138430ac8f5e589c18f83bfc9Affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before a7e761ba55efaa9c49e0afdd304bb78167af3429Affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before cd644e6dc72eec8d9d988717ea1c54f8668ded69Affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 9ed654e340f4c73bc6f0af2fbc90ac293e645ce0Affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before fe89b2f05b854847784f91127319172945c1faddAffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 7178e2a8027423b2af17ab95df73a749a5b72e5bAffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 858d2a4f67ff69e645a43487ef7ea7f28f06deaeAffected
LinuxLinux
  • 2.6.12Affected
  • before 2.6.12Not affected
  • 5.10.270 through 5.10.*Not affected
  • 5.15.221 through 5.15.*Not affected
  • 6.1.188 through 6.1.*Not affected
  • 6.6.157 through 6.6.*Not affected
  • 6.12.110 through 6.12.*Not affected
  • 6.18.16 through 6.18.*Not affected
  • 6.19.6 through 6.19.*Not affected
  • 7.0 and laterNot affected

References

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