CVE-2026-80851

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < 5f77ddb2756340c1b05381674ca025d52998005eaffected
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < 3d950e98f74af9611925a5226edced02155f6ed1affected
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < 6df4f05bc2991467939d7d80b6f7e121559cc3dfaffected
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < 1e995498d29784a06a2b2899370a1926cfc8410daffected
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < 498386b6d402737db1e2eeed4c385acbf0ef9e34affected
LinuxLinux4.7affected
LinuxLinux0 < 4.7unaffected
LinuxLinux6.12.108 <= 6.12.*unaffected
LinuxLinux6.18.49 <= 6.18.*unaffected
LinuxLinux7.1.13 <= 7.1.*unaffected
LinuxLinux7.2.3 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References