CVE-2025-68775Critical· 9.8▾ MidnightIn the Linux kernel, the following vulnerability has been resolved: net/handshake: duplicate handshake cancellations leak socket When a handshake request is cancelled it is removed from the handshake_net->hn_requests list, but it is st…
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 53.9 · likelihood 0.1 · exploitation 0
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Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake. The CVSS score shown above comes from the assigning CNA record, not NVD.
Exploit-prediction probability, daily snapshots since Oct 16.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CVEORG
0.5%
Last analysed / modified upstream
In the Linux kernel, the following vulnerability has been resolved:
net/handshake: duplicate handshake cancellations leak socket
When a handshake request is cancelled it is removed from the handshake_net->hn_requests list, but it is still present in the handshake_rhashtbl until it is destroyed.
If a second cancellation request arrives for the same handshake request, then remove_pending() will return false... and assuming HANDSHAKE_F_REQ_COMPLETED isn't set in req->hr_flags, we'll continue processing through the out_true label, where we put another reference on the sock and a refcount underflow occurs.
This can happen for example if a handshake times out - particularly if the SUNRPC client sends the AUTH_TLS probe to the server but doesn't follow it up with the ClientHello due to a problem with tlshd. When the timeout is hit on the server, the server will send a FIN, which triggers a cancellation request via xs_reset_transport(). When the timeout is hit on the client, another cancellation request happens via xs_tls_handshake_sync().
Add a test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED) in the pending cancel path so duplicate cancels can be detected.
Linux >= 3b3009ea8abb713b022d94fba95ec270cf6e7eae < 011ae80c49d9bfa5b4336f8bd387cd25c7593663Linux >= 3b3009ea8abb713b022d94fba95ec270cf6e7eae < e1641177e7fb48a0a5a06658d4aab51da6656659Linux >= 3b3009ea8abb713b022d94fba95ec270cf6e7eae < 3c330f1dee3cd92b57e19b9d21dc8ce5970b09beLinux >= 3b3009ea8abb713b022d94fba95ec270cf6e7eae < 15564bd67e2975002f2a8e9defee33e321d3183fLinux 6.4Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Connected by shared product, vendor, weakness, or advisory.
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