Service interruption via stale SunRPC timeout flag
Published Dec 28, 2024 · Updated Aug 5, 2026
NULL pointer dereference in affected Linux kernel releases allows remote attackers to interrupt service through SunRPC TCP transport resets. Resetting a transport clears transport->sock but leaves XPRT_SOCK_UPD_TIMEOUT set, so xs_tcp_send_request calls xs_tcp_set_socket_timeouts with a NULL socket. An existing NFSv4 client connection and a malicious server or on-path attacker are required; the fault wedges the mount and can panic configured systems.
Summary
What happened
NULL pointer dereference in affected Linux kernel releases allows remote attackers to interrupt service through SunRPC TCP transport resets. Resetting a transport clears transport->sock but leaves XPRT_SOCK_UPD_TIMEOUT set, so xs_tcp_send_request calls xs_tcp_set_socket_timeouts with a NULL socket. An existing NFSv4 client connection and a malicious server or on-path attacker are required; the fault wedges the mount and can panic configured systems.
The record
- CVE
- CVE-2024-56688
- Published
- Dec 28, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-476, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 28, 2024CVE 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=4.11
- Affected versionversion=7196dbb02ea05835b9ee56910ee82cb55422c7f1 <3811172e8c98ceebd12fe526ca6cb37a1263c964
- Affected versionversion=7196dbb02ea05835b9ee56910ee82cb55422c7f1 <4db9ad82a6c823094da27de4825af693a3475d51
- Affected versionversion=7196dbb02ea05835b9ee56910ee82cb55422c7f1 <638a8fa5a7e641f9401346c57e236f02379a0c40
- Affected versionversion=7196dbb02ea05835b9ee56910ee82cb55422c7f1 <66d11ca91bf5100ae2e6b5efad97e58d8448843a
- Affected versionversion=7196dbb02ea05835b9ee56910ee82cb55422c7f1 <86a1f9fa24804cd7f9d7dd3f24af84fc7f8ec02e
- Affected versionversion=7196dbb02ea05835b9ee56910ee82cb55422c7f1 <87a95ee34a48dfad198a2002e4966e1d63d53f2b
- Affected versionversion=7196dbb02ea05835b9ee56910ee82cb55422c7f1 <cc91d59d34ff6a6fee1c0b48612081a451e05e9a
- Affected versionversion=7196dbb02ea05835b9ee56910ee82cb55422c7f1 <fe6cbf0b2ac3cf4e21824a44eaa336564ed5e960
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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