Linux Kernel up to 6.12.92/7.0.11 net/handshake handshake.c handshake_nl_accept_doit req use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k4.66-

Summaryinfo

A vulnerability categorized as very critical has been discovered in Linux Kernel up to 6.12.92/7.0.11. The affected element is the function handshake_nl_accept_doit of the file net/handshake/handshake.c of the component net/handshake. Such manipulation of the argument req leads to use after free. This vulnerability is listed as CVE-2026-64523. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.92/7.0.11. It has been rated as very critical. Affected by this issue is the function handshake_nl_accept_doit of the file net/handshake/handshake.c of the component net/handshake. The manipulation of the argument req with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net/handshake: Take a long-lived file reference at submit handshake_nl_accept_doit() needs the file pointer backing req->hr_sk->sk_socket to survive the window between handshake_req_next() and the subsequent FD_PREPARE() and get_file(). The submit-side sock_hold() does not provide that. sk_refcnt keeps struct sock alive, but struct socket is owned by sock->file: when the consumer fputs the last file reference, sock_release() tears the socket down regardless of any sock_hold. Add an hr_file pointer to struct handshake_req and acquire an explicit reference on sock->file during handshake_req_submit(). handshake_complete() and handshake_req_cancel() release the reference on the completion-bit-winning path. The submit error path must also release the file reference, but after rhashtable insertion a concurrent handshake_req_cancel() can discover the request and race the error path. Gate the error-path cleanup -- sk_destruct restoration, fput, and request destruction -- with test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED), the same serialization handshake_complete() and handshake_req_cancel() already use. When cancel has already claimed ownership, the submit error path returns without touching the request; socket teardown handles final destruction. The accept-side dereferences are not yet retargeted; that change comes in the next patch.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-64523 since 07/19/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 07/25/2026).

Upgrading to version 6.12.93 or 7.0.12 eliminates this vulnerability. Applying the patch 685b10dd0e32c7782cead16c8cf055c609678583/16eaba5aa89c04eea125905bb8f988c1897f4f29/09dba37eee70d0596e26645015f1aa95a9848e9d is able to eliminate this problem.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-48867). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.93/7.0.12
Patch: 685b10dd0e32c7782cead16c8cf055c609678583/16eaba5aa89c04eea125905bb8f988c1897f4f29/09dba37eee70d0596e26645015f1aa95a9848e9d

Timelineinfo

07/19/2026 CVE reserved
07/25/2026 +6 days Advisory disclosed
07/25/2026 +0 days VulDB entry created
07/25/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64523 (🔒)
GCVE (CVE): GCVE-0-2026-64523
GCVE (VulDB): GCVE-100-383048
EUVD: 🔒

Entryinfo

Created: 07/25/2026 12:06
Updated: 07/25/2026 22:52
Changes: 07/25/2026 12:06 (61), 07/25/2026 22:52 (1)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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