CVE-2013-4549: QXmlSimpleReader in Qt before 5.2 allows context-dependent attackers to cause a denial of service (memory cons

Routine

MEDIUM 5.0UPGRADEDOWNGRADE

CVE-2013-4549 is a medium-severity flaw (CVSS 5.0) affecting qt, qt. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

QXmlSimpleReader in Qt before 5.2 allows context-dependent attackers to cause a denial of service (memory consumption) via an XML Entity Expansion (XEE) attack.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	3.1% (top 12%)
CISA exploited list	No
Weakness	CWE-20
Published	2013-12-23
Last modified	2026-06-16

Publisher (CNA): Red Hat, Inc. · Vendor: digia · qt

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

Am I affected?

Timeline

2013-12-23 22:55 UTCPublished CVE record published
2026-06-16 23:57 UTCUpdated Record last modified

digia qt UPGRADE

Affected: <= 5.1.0

Fixed in: newer than 5.1.0

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 5.1.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade qt

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade qt

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

qt qt DOWNGRADE

Affected: 5.0.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.0.2

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 5.0.2 (Debian / Ubuntu)

apt-cache madison qt sudo apt install qt=<VERSION_BEFORE_5.0.2> sudo apt-mark hold qt

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

dnf --showduplicates list qt sudo dnf downgrade qt-<VERSION_BEFORE_5.0.2> sudo dnf versionlock add qt

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.

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-2013-4549?

qt: upgrade to newer than 5.1.0; qt: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2013-4549 being exploited?

CVE-2013-4549 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-2013-4549 affect?

CVE-2013-4549 affects qt, qt. Severity is medium (CVSS 5.0). QXmlSimpleReader in Qt before 5.2 allows context-dependent attackers to cause a denial of service (memory consumption) via an XML Entity Expansion (XEE) attack.

How urgent is CVE-2013-4549?

Priority 39/100. No elevated risk signals yet.

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References

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