CVE-2013-4459: 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

Routine

LOW 3.3WATCHLISTDOWNGRADEMITIGATE

CVE-2013-4459 is a low-severity flaw (CVSS 3.3) affecting lightdm, ubuntu linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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, which allows local users to bypass intended restrictions by leveraging the Guest account.

Why this priority

Public exploit reference
On your watchlist

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

Risk facts

CVSS score	3.3 (Low)
EPSS exploit chance	0.4% (top 62%)
CISA exploited list	No
Weakness	CWE-264
Published	2013-11-23
Last modified	2026-06-16

Publisher (CNA): Red Hat, Inc. · 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

2013-11-23 18:55 UTCPublished CVE record published
2026-06-16 23:57 UTCUpdated Record last modified

robert ancell lightdm DOWNGRADE

Affected: 1.7.5 · 1.7.6 · 1.7.7 · 1.7.8 · 1.7.9 · 1.7.10 · 1.7.11 · 1.7.12

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.7.5

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.7.5 (Debian / Ubuntu)

apt-cache madison lightdm sudo apt install lightdm=<VERSION_BEFORE_1.7.5> sudo apt-mark hold lightdm

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

dnf --showduplicates list lightdm sudo dnf downgrade lightdm-<VERSION_BEFORE_1.7.5> 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: 13.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 13.10

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.

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-2013-4459?

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-2013-4459 being exploited?

CVE-2013-4459 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-2013-4459 affect?

CVE-2013-4459 affects lightdm, ubuntu linux. Severity is low (CVSS 3.3). 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, which allows local users to bypass intended restrictions by leveraging the Guest account.

How urgent is CVE-2013-4459?

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

Software pages

Ubuntu vulnerabilities

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References

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