CVE-2012-0943: debian/guest-account in Light Display Manager (lightdm) 1.0.x before 1.0.6 and 1.1.x before 1.1.7, as used in

Routine

LOW 2.1WATCHLISTDOWNGRADEMITIGATE

CVE-2012-0943 is a low-severity flaw (CVSS 2.1) affecting lightdm, ubuntu linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

debian/guest-account in Light Display Manager (lightdm) 1.0.x before 1.0.6 and 1.1.x before 1.1.7, as used in Ubuntu Linux 11.10, allows local users to delete arbitrary files via a space in the name of a file in /tmp. NOTE: this identifier was SPLIT per ADT1/ADT2 due to different codebases and affected versions. CVE-2012-6648 has been assigned for the gdm-guest-session issue.

Why this priority

Public exploit reference
On your watchlist

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

Risk facts

CVSS score	2.1 (Low)
EPSS exploit chance	0.8% (top 45%)
CISA exploited list	No
Weakness	CWE-264
Published	2014-05-22
Last modified	2026-06-16

Publisher (CNA): Canonical Ltd. · Vendor: canonical · robert ancell

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

Am I affected?

Timeline

2014-05-22 23:55 UTCPublished CVE record published
2026-06-16 23:38 UTCUpdated Record last modified

robert ancell lightdm DOWNGRADE

Affected: 1.0.0 · 1.0.1 · 1.0.2 · 1.0.3 · 1.0.4 · 1.0.5 · 1.1.0 · 1.1.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0.0

1. Check installed version

apt-cache policy lightdm || rpm -q lightdm || lightdm --version

2. No fixed release: DOWNGRADE to a release before 1.0.0 (Debian / Ubuntu)

apt-cache madison lightdm sudo apt install lightdm=<VERSION_BEFORE_1.0.0> sudo apt-mark hold lightdm

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list lightdm sudo dnf downgrade lightdm-<VERSION_BEFORE_1.0.0> sudo dnf versionlock add lightdm

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

canonical ubuntu linux MITIGATE

Affected: 11.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.10

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: LightDM 1.0.6 - Arbitrary File Deletion

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-2012-0943?

lightdm: downgrade or apply the listed mitigation; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2012-0943 being exploited?

CVE-2012-0943 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-2012-0943 affect?

CVE-2012-0943 affects lightdm, ubuntu linux. Severity is low (CVSS 2.1). debian/guest-account in Light Display Manager (lightdm) 1.0.x before 1.0.6 and 1.1.x before 1.1.7, as used in Ubuntu Linux 11.10, allows local users to delete arbitrary files via a space in the name of a file in /tmp. NOTE: this identifier

How urgent is CVE-2012-0943?

Priority 31/100. Public exploit reference; On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities

Related CVEs

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CVE-2015-8316 MEDIUM 5.9 DOWNGRADE Array index error in LightDM (aka Light Display Manager) 1.14.3, 1.16.x before 1.16.6 when the XDMCP server is
CVE-2013-4459 LOW 3.3 DOWNGRADE MITIGATE LightDM 1.7.5 through 1.8.3 and 1.9.x before 1.9.2 does not apply the AppArmor profile to the Guest account, w
CVE-2013-4331 LOW 2.1 DOWNGRADE Light Display Manager (aka LightDM) 1.4.x before 1.4.3, 1.6.x before 1.6.2, and 1.7.x before 1.7.14 uses 0664

References

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