Severity by source
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Local attack with low privileges, no interaction, low availability impact only.
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
7DescriptionCVE.org
A vulnerability has been found in 9fans plan9port up to 9da5b44 and classified as problematic. Affected by this vulnerability is the function value_decode in the library src/libsec/port/x509.c. The manipulation leads to null pointer dereference. Local access is required to approach this attack. The exploit has been disclosed to the public and may be used. This product takes the approach of rolling releases to provide continious delivery. Therefore, version details for affected and updated releases are not available. The identifier of the patch is deae8939583d83fd798fca97665e0e94656c3ee8. It is recommended to apply a patch to fix this issue.
AnalysisAI
Local denial of service in 9fans plan9port via a null pointer dereference in the X.509 certificate parsing function value_decode. A local attacker with low privileges can crash applications using the libsec port, disrupting availability. Public exploit code is available, but EPSS indicates low exploitation likelihood and no active exploitation has been reported via CISA KEV.
Technical ContextAI
The vulnerability resides in the plan9port library, a port of Plan 9 from Bell Labs to Unix-like systems, specifically in the X.509 certificate parsing code at src/libsec/port/x509.c. The function value_decode misuses resources, leading to a null pointer dereference (CWE-404) when processing malformed input. The affected product is 9fans plan9port (cpe:2.3:a:9fans:plan9port:*), a rolling-release distribution where version boundaries are defined by commit hashes rather than traditional version numbers.
RemediationAI
Apply the patch commit deae8939583d83fd798fca97665e0e94656c3ee8 from the 9front repository to the plan9port source tree. Since the project uses rolling releases, updating to the latest source code will include the fix. No new versioned release is available. As a workaround, restrict local access to processes using the libsec library if certificate parsing from untrusted local inputs is a concern, though this may not fully mitigate the risk.
Same weakness CWE-404 – Improper Resource Shutdown or Release
View allSame technique Denial Of Service
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External POC / Exploit Code
Leaving vuln.today
EUVD-2025-20761