CVE-2026-52993 tipc: fix double-free in tipc_buf_append()
A double-free vulnerability in the Linux kernel's TIPC module allows attackers to potentially execute arbitrary code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-52993?
CVE-2026-52993 is a critical use after free vulnerability in Linux kernel, published on 24 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
tipc: fix double-free in tipc_buf_append()
tipc_msg_validate() can potentially reallocate the skb it is validating, freeing the old one. In tipc_buf_append(), it was being called with a pointer to a local variable which was a copy of the caller's skb pointer.
If the skb was reallocated and validation subsequently failed, the error handling path would free the original skb pointer, which had already been freed, leading to double-free.
Fix this by checking if head now points to a newly allocated reassembled skb. If it does, reassign *headbuf for later freeing operations.
Which versions are affected by CVE-2026-52993?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-52993?
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-2026-52993 being exploited?
There is no known exploitation of CVE-2026-52993 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in Linux kernel
Sources
Also known as A-500022799, ASB-A-500022799, BELL-CVE-2026-52993, DEBIAN-CVE-2026-52993, GHSA-m86q-cgj9-94c8, ROOT-OS-DEBIAN-11-CVE-2026-52993 and 4 more.