CVE-2007-1189: Integer overflow in the envwrite function in the Alcatel-Lucent Bell Labs Plan 9 kernel allows local users to

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HIGH 7.2MITIGATE

CVE-2007-1189 is a high-severity flaw (CVSS 7.2) affecting plan 9. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Integer overflow in the envwrite function in the Alcatel-Lucent Bell Labs Plan 9 kernel allows local users to overwrite certain memory addresses with kernel memory via a large n argument, as demonstrated by (1) modifying the iseve function to gain privileges and (2) making the devpermcheck function grant unrestricted device permissions.

Why this priority

High severity
Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.2 (High)
EPSS exploit chance	0.8% (top 43%)
CISA exploited list	No
Published	2007-03-02
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: bell labs

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2007-03-02 21:18 UTCPublished CVE record published
2026-06-16 22:37 UTCUpdated Record last modified

bell labs plan 9 MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: Plan 9 Kernel - 'devenv.c OTRUNC/pwrite' Local Privilege Escalation

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2007-1189?

plan 9: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2007-1189 being exploited?

CVE-2007-1189 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2007-1189 affect?

CVE-2007-1189 affects plan 9. Severity is high (CVSS 7.2). Integer overflow in the envwrite function in the Alcatel-Lucent Bell Labs Plan 9 kernel allows local users to overwrite certain memory addresses with kernel memory via a large n argument, as demonstrated by (1) modifying the iseve function

How urgent is CVE-2007-1189?

Priority 44/100. High severity; Public exploit reference

References

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