UBUNTU-CVE-2025-68775
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.
02 / AFFECTED SOFTWARE
Affected packages
11 explicit affected versions
50 explicit affected versions
6 explicit affected versions
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6 explicit affected versions
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26 explicit affected versions
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35 explicit affected versions
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13 explicit affected versions
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1 explicit affected versions
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9 explicit affected versions
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43 explicit affected versions
8 explicit affected versions
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12 explicit affected versions
11 explicit affected versions
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10 explicit affected versions
1 explicit affected versions
7 explicit affected versions
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12 explicit affected versions
4 explicit affected versions
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36 explicit affected versions
16 explicit affected versions
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10 explicit affected versions
37 explicit affected versions
10 explicit affected versions
4 explicit affected versions
13 explicit affected versions
35 explicit affected versions
3 explicit affected versions
10 explicit affected versions
11 explicit affected versions
26 explicit affected versions
6 explicit affected versions
13 explicit affected versions
29 explicit affected versions
13 explicit affected versions
12 explicit affected versions
36 explicit affected versions
36 explicit affected versions
3 explicit affected versions
33 explicit affected versions
23 explicit affected versions
10 explicit affected versions
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14 explicit affected versions
11 explicit affected versions
5 explicit affected versions
12 explicit affected versions
4 explicit affected versions
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3 explicit affected versions
11 explicit affected versions
5 explicit affected versions
10 explicit affected versions
26 explicit affected versions
34 explicit affected versions
30 explicit affected versions
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11 explicit affected versions
4 explicit affected versions
13 explicit affected versions
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16 explicit affected versions
45 explicit affected versions
3 explicit affected versions
7 explicit affected versions
10 explicit affected versions
51 explicit affected versions
11 explicit affected versions
18 explicit affected versions
37 explicit affected versions
12 explicit affected versions
3 explicit affected versions
27 explicit affected versions
38 explicit affected versions
8 explicit affected versions
5 explicit affected versions
8 explicit affected versions
10 explicit affected versions
7 explicit affected versions
41 explicit affected versions
13 explicit affected versions
13 explicit affected versions
7 explicit affected versions
8 explicit affected versions
10 explicit affected versions
12 explicit affected versions
9 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
45 explicit affected versions
37 explicit affected versions
46 explicit affected versions
14 explicit affected versions
38 explicit affected versions
9 explicit affected versions
12 explicit affected versions
11 explicit affected versions
34 explicit affected versions
15 explicit affected versions
9 explicit affected versions
8 explicit affected versions
7 explicit affected versions
4 explicit affected versions
3 explicit affected versions
1 explicit affected versions
13 explicit affected versions
43 explicit affected versions
9 explicit affected versions
10 explicit affected versions
8 explicit affected versions
40 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
9 explicit affected versions
11 explicit affected versions
1 explicit affected versions
14 explicit affected versions
34 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/15564bd67e2975002f2a8e9defee33e321d3183f
- https://git.kernel.org/stable/c/011ae80c49d9bfa5b4336f8bd387cd25c7593663
- https://git.kernel.org/stable/c/15564bd67e2975002f2a8e9defee33e321d3183f
- https://git.kernel.org/stable/c/3c330f1dee3cd92b57e19b9d21dc8ce5970b09be
- https://git.kernel.org/stable/c/e1641177e7fb48a0a5a06658d4aab51da6656659
- https://ubuntu.com/security/CVE-2025-68775
- https://ubuntu.com/security/notices/USN-8177-1
- https://ubuntu.com/security/notices/USN-8177-2
- https://ubuntu.com/security/notices/USN-8179-1
- https://ubuntu.com/security/notices/USN-8179-2
- https://ubuntu.com/security/notices/USN-8179-3
- https://ubuntu.com/security/notices/USN-8179-4
- https://ubuntu.com/security/notices/USN-8183-1
- https://ubuntu.com/security/notices/USN-8183-2
- https://ubuntu.com/security/notices/USN-8184-1
- https://ubuntu.com/security/notices/USN-8185-1
- https://ubuntu.com/security/notices/USN-8185-2
- https://ubuntu.com/security/notices/USN-8203-1
- https://ubuntu.com/security/notices/USN-8204-1
- https://ubuntu.com/security/notices/USN-8245-1
- https://ubuntu.com/security/notices/USN-8257-1
- https://ubuntu.com/security/notices/USN-8258-1
- https://ubuntu.com/security/notices/USN-8260-1
- https://ubuntu.com/security/notices/USN-8261-1
- https://ubuntu.com/security/notices/USN-8265-1
- https://ubuntu.com/security/notices/USN-8440-1
- https://www.cve.org/CVERecord?id=CVE-2025-68775