In the Linux kernel, the following vulnerability has been resolved: sunrpc: fix null pointer dereference on zero-length checksum In… (CVE-2025-40129)
A vulnerability in the Linux kernel's sunrpc subsystem causes a null pointer dereference when processing a zero-length checksum. Specifically, in the function xdr_stream_decode_opaque_auth(), a zero-length checksum leads to checksum.data being set to NULL, which triggers a null pointer dereference in gss_krb5_verify_mic_v2(). This issue has been resolved by ensuring checksum.len is not less than the required minimum XDR_UNIT.
AI Analysis
Technical Summary
The Linux kernel sunrpc subsystem had a vulnerability (CVE-2025-40129) where a zero-length checksum in xdr_stream_decode_opaque_auth() caused checksum.data to be NULL. This NULL pointer was dereferenced in gss_krb5_verify_mic_v2(), leading to a denial of service via a kernel crash. The patch fixes this by validating that checksum.len is not less than XDR_UNIT before use.
Potential Impact
This vulnerability results in a denial of service (DoS) condition due to a null pointer dereference in the kernel, causing a crash. There is no indication of confidentiality or integrity impact. The CVSS vector indicates network attack vector, low attack complexity, no privileges required, no user interaction, and an impact limited to availability.
Mitigation Recommendations
A fix for this vulnerability has been implemented in the Linux kernel. Since no explicit patch links or vendor advisory are provided, users should apply the latest kernel updates that include this fix. Patch status is not yet confirmed — check the official Linux kernel advisories or distribution security updates for current remediation guidance.
In the Linux kernel, the following vulnerability has been resolved: sunrpc: fix null pointer dereference on zero-length checksum In… (CVE-2025-40129)
Description
A vulnerability in the Linux kernel's sunrpc subsystem causes a null pointer dereference when processing a zero-length checksum. Specifically, in the function xdr_stream_decode_opaque_auth(), a zero-length checksum leads to checksum.data being set to NULL, which triggers a null pointer dereference in gss_krb5_verify_mic_v2(). This issue has been resolved by ensuring checksum.len is not less than the required minimum XDR_UNIT.
CVSS v3.1
Score 7.5high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel sunrpc subsystem had a vulnerability (CVE-2025-40129) where a zero-length checksum in xdr_stream_decode_opaque_auth() caused checksum.data to be NULL. This NULL pointer was dereferenced in gss_krb5_verify_mic_v2(), leading to a denial of service via a kernel crash. The patch fixes this by validating that checksum.len is not less than XDR_UNIT before use.
Potential Impact
This vulnerability results in a denial of service (DoS) condition due to a null pointer dereference in the kernel, causing a crash. There is no indication of confidentiality or integrity impact. The CVSS vector indicates network attack vector, low attack complexity, no privileges required, no user interaction, and an impact limited to availability.
Mitigation Recommendations
A fix for this vulnerability has been implemented in the Linux kernel. Since no explicit patch links or vendor advisory are provided, users should apply the latest kernel updates that include this fix. Patch status is not yet confirmed — check the official Linux kernel advisories or distribution security updates for current remediation guidance.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-c9g4-75m8-v388
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2025-40129"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6a6b72d69c2644c7f847abd2
Added to database: 07/30/2026, 15:50:46 UTC
Last enriched: 07/30/2026, 16:42:35 UTC
Last updated: 09/10/2026, 19:26:50 UTC
Views: 12
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