In the Linux kernel, the following vulnerability has been resolved:
tcp: exclude old ACKs from tcp fast path
Exclude old ACKs before SND.UNA from the tcp fast path as well as ACKs after SND.NXT.
Such ACKs will fall through to the slow path, where tcp_ack() performs the appropriate validation and challenge ACK handling according to RFC5961 and Commit 3d501dd326fb1c7 ("tcp: do not accept ACK of bytes we never sent").
This prevents old ACKs from being accepted or modifying connection state as part of the fast path before appropriate ACK validation is applied. In particular, this prevents payload carried by a segment with an excessively old ACK from advancing RCV.NXT before the ACK is rejected.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon_linux_2023 | — | Upgrade python3-perf-debuginfoUpgrade kernel-debuginfo-common-aarch64Upgrade perfUpgrade python3-perfUpgrade kernelUpgrade kernel-livepatch-6.1.189-236.399Upgrade kernel-modules-extraUpgrade perf-debuginfoUpgrade microvm-kernelUpgrade kernel-headersUpgrade kernel-toolsUpgrade kernel-modules-extra-commonUpgrade bpftool-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-tools-develUpgrade kernel-debuginfoUpgrade kernel-tools-debuginfoUpgrade kernel-develUpgrade bpftool | Nov 2, 2026 | Oct 6, 2026 |
| Debian | — | Upgrade linuxUpgrade linux-6.12 | Oct 20, 2026 | Oct 6, 2026 |
| Redhat_linux | — | No solution exists | Oct 13, 2026 | Oct 6, 2026 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Oct 13, 2026 | Oct 6, 2026 |
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