Use-after-free in Linux kernel - CVE-2026-31680
Published: April 25, 2026
Vulnerability identifier: #VU127873
CSH Severity: Low
CVSSv4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-31680
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerable software:
Linux kernel
Linux kernel
Software vendor:
Linux Foundation
Linux Foundation
Description
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a use-after-free in ip6fl_seq_show() when reading /proc/net/ip6_flowlabel concurrently with flowlabel release. A local user can trigger concurrent access to dereference freed option state and cause a denial of service.
The issue occurs because the flowlabel remains reachable through the global hash table under RCU after its option state has been freed.
Remediation
Install security update from vendor's repository.
External links
- https://git.kernel.org/stable/c/3c54b66c83fb8fcbde8e6a7bf90b65856e39f827
- https://git.kernel.org/stable/c/414726b69921fe6355ae453f5b35e68dd078342a
- https://git.kernel.org/stable/c/4b6798024f7b2d535f3db1002c760143cdbd1bd3
- https://git.kernel.org/stable/c/572ce62778519a7d4d1c15f55dd2e45a474133c4
- https://git.kernel.org/stable/c/5a6b15f861b7c1304949e3350d23490a5fe429fd
- https://git.kernel.org/stable/c/6c7fbdb8ffde6413640de7cfbd7c976c353e89f8
- https://git.kernel.org/stable/c/8027964931785cb73d520ac70a342a3dc16c249b
- https://git.kernel.org/stable/c/9ca562bb8e66978b53028fa32b1a190708e6a091