CVE-2026-43339 ipv6: prevent possible UaF in addrconf_permanent_addr()
A use-after-free vulnerability in the Linux kernel IPv6 subsystem allows attackers to potentially execute code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-43339?
CVE-2026-43339 is a high-severity use after free vulnerability in Linux kernel, published on 8 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ipv6: prevent possible UaF in addrconf_permanent_addr()
The mentioned helper try to warn the user about an exceptional condition, but the message is delivered too late, accessing the ipv6 after its possible deletion.
Reorder the statement to avoid the possible UaF; while at it, place the warning outside the idev->lock as it needs no protection.
Weakness: CWE-416
Which versions are affected by CVE-2026-43339?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43339?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-43339 being exploited?
There is no known exploitation of CVE-2026-43339 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43339, DEBIAN-CVE-2026-43339, GHSA-4v8f-jwm3-5f44, ROOT-OS-DEBIAN-11-CVE-2026-43339, ROOT-OS-UBUNTU-2204-CVE-2026-43339, ROOT-OS-UBUNTU-2404-CVE-2026-43339 and 1 more.