CVE-2026-80637: netfilter: synproxy: fix unaligned memory access in timestamp adjustment
In the Linux kernel, the following vulnerability has been resolved:
netfilter: synproxy: fix unaligned memory access in timestamp adjustment
Use getunalignedbe32() and putunalignedbe32() to safely read and write the timestamp fields. This prevents performance degradation due to unaligned memory access or even a crash on strict alignment architectures.
This follows the implementation of timestamp parsing in the networking stack at tcpparseoptions() and synproxyparseoptions().
Event History
Frequently Asked Questions
Which systems are most likely to be affected?
Systems using the Linux kernel's netfilter SYNPROXY functionality are relevant, particularly when SYNPROXY adjusts TCP timestamp fields. Strict-alignment architectures can experience a crash, while unaligned access can also cause performance degradation.
What traffic handling triggers the issue?
The issue occurs during SYNPROXY timestamp adjustment when timestamp fields are read or written at unaligned memory addresses. The resolved code uses safe unaligned big-endian reads and writes for those fields.