Kernel compromise via KCM receive-queue race
Published May 1, 2025 · Updated Aug 5, 2026
Race condition in the Linux kernel KCM receive path allows local users to read or write kernel memory or crash the host through concurrent calls. kcm_recvmsg() receives from sk_receive_queue without the locking used by requeue_rx_msgs(), allowing one thread to retain an skb after another dequeues or frees it. An unprivileged local account can create KCM sockets and drive both sides of the race without user interaction; remote TCP traffic alone cannot reach the racing window.
Summary
What happened
Race condition in the Linux kernel KCM receive path allows local users to read or write kernel memory or crash the host through concurrent calls. kcm_recvmsg() receives from sk_receive_queue without the locking used by requeue_rx_msgs(), allowing one thread to retain an skb after another dequeues or frees it. An unprivileged local account can create KCM sockets and drive both sides of the race without user interaction; remote TCP traffic alone cannot reach the racing window.
The record
- CVE
- CVE-2022-49814
- Published
- May 1, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-362, T1499.004, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 1, 2025CVE publishedPublication date reported by the CVE source.
- Aug 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.6
- Affected versionversion=ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 <22f6b5d47396b4287662668ee3f5c1f766cb4259
- Affected versionversion=ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 <4154b6afa2bd639214ff259d912faad984f7413a
- Affected versionversion=ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 <5121197ecc5db58c07da95eb1ff82b98b121a221
- Affected versionversion=ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 <bf92e54597d842da127c59833b365d6faeeaf020
- Affected versionversion=ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 <ce57d6474ae999a3b2d442314087473a646a65c7
- Affected versionversion=ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 <d9ad4de92e184b19bcae4da10dac0275abf83931
- Affected versionversion=ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 <f7b0e95071bb4be4b811af3f0bfc3e200eedeaa3
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- syzbot C reproducer for skb_unlink faultproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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