CVE-2025-7209Public exploit

Local process crash via malformed ASN.1 value

Published Jul 9, 2025 · Updated Jul 9, 2025

NULL pointer dereference in Plan 9 from User Space 9da5b44 allows local users to crash a consuming process via malformed ASN.1 data. The value_decode function in src/libsec/port/x509.c reads through a null pointer while decoding a crafted ASN.1 value. Exploitation requires local code or a local workflow that submits the malformed input to libsec, and the demonstrated result is process termination rather than data access or code execution.

CVSS severity5.5
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Plan 9 from User Space 9da5b44 allows local users to crash a consuming process via malformed ASN.1 data. The value_decode function in src/libsec/port/x509.c reads through a null pointer while decoding a crafted ASN.1 value. Exploitation requires local code or a local workflow that submits the malformed input to libsec, and the demonstrated result is process termination rather than data access or code execution.

The record

CVE
CVE-2025-7209
Published
Jul 9, 2025
Updated
Jul 9, 2025
Vendor
9fans
Product
Plan 9 from User Space
Classifications
CWE-404, CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 9, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2025Record 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.

  1. Affected versionversion=9da5b44

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

9fans · Plan 9 from User Spaceversion=9da5b44

Published CVSS scores

1.9VulDBCVSS: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
3.3VulDBCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
1.7VulDBAV:L/AC:L/Au:S/C:N/I:N/A:P

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-404Improper Resource Shutdown or Release
CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

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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