CVE-2026-53212 netfilter: nft_tunnel: fix use-after-free on object destroy
A use-after-free vulnerability in the Linux kernel's netfilter tunnel module allows attackers to execute arbitrary code or escalate privileges via crafted network packets.
- 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-2026-53212?
CVE-2026-53212 is a high-severity use after free vulnerability in Linux kernel, published on 25 Jun 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:
netfilter: nft_tunnel: fix use-after-free on object destroy
nft_tunnel_obj_destroy() calls metadata_dst_free() which directly kfree()s the metadata_dst, ignoring the dst_entry refcount. Packets that took a reference via dst_hold() in nft_tunnel_obj_eval() and are still queued (e.g. in a netem qdisc) are left with a dangling pointer. When these packets are eventually dequeued, dst_release() operates on freed memory.
Replace metadata_dst_free() with dst_release() so the metadata_dst is freed only after all references are dropped. The dst subsystem already handles metadata_dst cleanup in dst_destroy() when DST_METADATA is set.
Weakness: CWE-416
Which versions are affected by CVE-2026-53212?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-53212?
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-2026-53212 being exploited?
There is no known exploitation of CVE-2026-53212 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-90854, BELL-CVE-2026-53212, DEBIAN-CVE-2026-53212, GHSA-j962-fx34-5263, ROOT-OS-DEBIAN-11-CVE-2026-53212, ROOT-OS-DEBIAN-12-CVE-2026-53212 and 3 more.