CVE-2025-71263
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn UNIX Fourth Research Edition (v4), the su command is vulnerable to a buffer overflow due to the 'password' variable having a fixed size of 100 bytes. A local user can exploit this to gain root privileges. It is unlikely that UNIX v4 is running anywhere outside of a very small number of lab environments. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceBuffer overflow in UNIX Fourth Research Edition (v4) su command where the password variable uses a fixed 100-byte buffer. A local attacker can overflow this buffer to overwrite memory and execute arbitrary code with root privileges.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 4CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the operating system versionRun `uname -a` or check `/etc/os-release` to determine if the system is Opengroup UNIX Fourth Research Edition v4Affected if The operating system is Opengroup UNIX v4 (version 4)
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Locate the su command binaryCheck for the presence of the su binary using `ls -la /bin/su /usr/bin/su 2>/dev/null`Affected if The su command binary exists at standard paths like /bin/su or /usr/bin/su
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Retrieve su binary version informationRun `su -v` or `su --version` if available to display the su command versionAffected if The su binary version reports as the Opengroup UNIX v4 implementation
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Verify file permissions on the su binaryCheck ownership and permissions with `ls -la /bin/su` or `ls -la /usr/bin/su` - look for world-executable or group-executable permissionsAffected if The su binary is executable by unprivileged users (mode includes o+x or g+x)
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Confirm local user access to the systemList local user accounts with `getent passwd` or check `/etc/passwd` to identify which users have shell accessAffected if There are local user accounts other than root on the system
You are affected if you are running Opengroup UNIX Fourth Research Edition v4 with the su command installed and accessible to untrusted local users.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataThis affects end-of-life software no longer maintained. Primary mitigation is to not run UNIX v4 in any production or accessible lab environments. If present, isolate completely from networks and restrict to trusted local users only.
- Consultation1.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-71263 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-71263 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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