CVE-2026-80851 gtp: serialize PDP context updates
A race condition in the Linux kernel GTP module allows concurrent PDP context deletions to cause a general protection fault and system crash.
- 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-2026-80851?
CVE-2026-80851 is a vulnerability in Linux, published on 4 Sep 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:
gtp: serialize PDP context updates
PDP contexts can be deleted through GTP_CMD_DELPDP or while the GTP network device is being unregistered. The latter is serialized by RTNL, but the generic-netlink delete path only holds RCU.
Running both paths concurrently can therefore make both paths delete the same PDP context. The issue was found through static analysis and reproduced on a KASAN-enabled kernel by a simple two-thread program racing GTP_CMD_DELPDP against RTM_DELLINK:
Oops: general protection fault, probably for non-canonical address KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127] RIP: gtp_genl_del_pdp+0x1c1/0x420 [gtp] RBP: dead000000000122
The second deletion dereferenced the poisoned hlist pprev pointer.
Serialize gtp_pdp_add(), gtp_genl_del_pdp(), and gtp_dellink() with a shared mutex. Keep the mutex held until the final use of a PDP context in the NEWPDP path, and keep the RCU read-side section around the complete PDP context use in the DELPDP path.
Which versions are affected by CVE-2026-80851?
How do I fix CVE-2026-80851?
Apply the vendor's patch.
Is CVE-2026-80851 being exploited?
There is no known exploitation of CVE-2026-80851 in the wild and no public exploit code.
Sources
Also known as AZL-99569, BELL-CVE-2026-80851, DEBIAN-CVE-2026-80851, GHSA-wq34-548c-54v3, UBUNTU-CVE-2026-80851.