Remote service interruption via NFSD tracepoint null dereference
Published Dec 8, 2025 · Updated Aug 5, 2026
Denial of service in affected Linux NFSD versions allows remote attackers to exhaust server threads via a crafted NFSv4 COMPOUND READ. nfsd4_read_release invokes trace_nfsd_read_done after a READ without a filehandle leaves rd_rqstp and rd_fhp null, causing a null dereference. Exposure requires reachable TCP port 2049 and enabled NFSD read tracing; repeated requests exhaust NFSD threads, while panic_on_oops causes a kernel panic.
Summary
What happened
Denial of service in affected Linux NFSD versions allows remote attackers to exhaust server threads via a crafted NFSv4 COMPOUND READ. nfsd4_read_release invokes trace_nfsd_read_done after a READ without a filehandle leaves rd_rqstp and rd_fhp null, causing a null dereference. Exposure requires reachable TCP port 2049 and enabled NFSD read tracing; repeated requests exhaust NFSD threads, while panic_on_oops causes a kernel panic.
The record
- CVE
- CVE-2025-40324
- Published
- Dec 8, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 8, 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?
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- Affected versionversion=15a8b55dbb1ba154d82627547c5761cac884d810 <03524ccff698d4a77d096ed529073d91f5edee5d
- Affected versionversion=15a8b55dbb1ba154d82627547c5761cac884d810 <8f244b773c63fa480c9a3bd1ae04f5272f285e89
- Affected versionversion=15a8b55dbb1ba154d82627547c5761cac884d810 <a4948875ed0599c037dc438c11891c9012721b1d
- Affected versionversion=15a8b55dbb1ba154d82627547c5761cac884d810 <abb1f08a2121dd270193746e43b2a9373db9ad84
- Affected versionversion=3d0dcada384af22dec764c8374a2997870ec86ae
- Affected versionversion=5.10.220 <5.10.247
- Affected versionversion=5.15.154 <5.15.197
- Affected versionversion=6.1.24 <6.1.159
- Affected versionversion=6.2.11 <6.3
- Affected versionversion=6.3
- Affected versionversion=65a33135e91e6dd661ecdf1194b9d90c49ae3570 <930cb4fe3ab4061be31f20ee30bb72a66f7bb6d1
- Affected versionversion=b11d8162c24af4a351d21e2c804d25ca493305e3 <375fdd8993cecc48afa359728a6e70b280dde1c8
- Affected versionversion=b623a8e5d38a69a3ef8644acb1030dd7c7bc28b3 <2ac46606b2cc49e78d8e3d8f2685e79e9ba73020
What conditions does exploitation require?
What is affected?
Published CVSS scores
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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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