Use-After-Free in Linux Kernel Pppol2tp Functionality
CVE-2026-68398
Key Information:
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What is CVE-2026-68398?
The vulnerability within the Linux kernel occurs in the pppol2tp_recv() function, which fails to properly manage memory deallocation in a multi-threaded environment. This oversight allows an unprivileged user to potentially exploit the system by dereferencing a channel that has already been freed, leading to unpredictable behavior or system instability. The issue arises from inadequate synchronization during the tear-down of PPP connections, resulting in the possibility of data corruption or memory access violations. The resolution includes deferring memory release to ensure proper grace periods are adhered to, thereby safeguarding against concurrent access by multiple threads.
Affected Version(s)
Linux ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741 < 4e47f1ac188ece11d6fdabe44166a2776cc5bd4e
Linux ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741 < 110b765744b147c63882f5e9cb12931c5dc8d85f
Linux ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741 < 4bb84e964ff0fe0a171c965362de72f9820dbce9
Exploit Proof of Concept (PoC)
PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.