CVE-2026-23272: netfilter: nf_tables: unconditionally bump set->nelems before insertion
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nftables: unconditionally bump set->nelems before insertion
In case that the set is full, a new element gets published then removed without waiting for the RCU grace period, while RCU reader can be walking over it already.
To address this issue, add the element transaction even if set is full, but toggle the setfull flag to report -ENFILE so the abort path safely unwinds the set to its previous state.
As for element updates, decrement set->nelems to restore it.
A simpler fix is to call synchronizercu() in the error path. However, with a large batch adding elements to already maxed-out set, this could cause noticeable slowdown of such batches.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-23272?
CVE-2026-23272 is classified with a high severity level due to the potential for information exposure and denial of service.
How do I fix CVE-2026-23272?
To resolve CVE-2026-23272, update to the latest version of the Linux kernel where the vulnerability has been patched.
What systems are affected by CVE-2026-23272?
CVE-2026-23272 affects the Linux kernel, specifically the netfilter nf_tables module.
What are the potential impacts of CVE-2026-23272?
The impacts of CVE-2026-23272 include possible denial of service and memory corruption through mishandling of elements in sets.
Is CVE-2026-23272 actively exploited in the wild?
As of the latest information, there are no confirmed reports of CVE-2026-23272 being actively exploited in the wild.