CVE-2011-1944: Integer overflow in xpath.c in libxml2 2.6.x through 2.6.32 and 2.7.x through 2.7.8, and libxml 1.8.16 and ear

Q: How do I fix CVE-2011-1944?

libxml2: downgrade or apply the listed mitigation; libxml: upgrade to newer than 1.8.16. Exact commands for each OS are on this page.

Q: Is CVE-2011-1944 being exploited?

CVE-2011-1944 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2011-1944 affect?

CVE-2011-1944 affects libxml2, libxml. Severity is high (CVSS 9.3). Integer overflow in xpath.c in libxml2 2.6.x through 2.6.32 and 2.7.x through 2.7.8, and libxml 1.8.16 and earlier, allows context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted XM

Q: How urgent is CVE-2011-1944?

Priority 62/100. Critical severity; EPSS top 4%: very likely to be exploited; Public exploit reference

This week

HIGH 9.3DOWNGRADEUPGRADE

CVE-2011-1944 is a high-severity flaw (CVSS 9.3) affecting libxml2, libxml. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Integer overflow in xpath.c in libxml2 2.6.x through 2.6.32 and 2.7.x through 2.7.8, and libxml 1.8.16 and earlier, allows context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted XML file that triggers a heap-based buffer overflow when adding a new namespace node, related to handling of XPath expressions.

Why this priority

Critical severity
EPSS top 4%: very likely to be exploited
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	9.3 (High)
EPSS exploit chance	13.4% (top 4%)
CISA exploited list	No
Weakness	CWE-189
Published	2011-09-02
Last modified	2026-06-16

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

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

Am I affected?

Timeline

2011-09-02 16:55 UTCPublished CVE record published
2026-06-16 23:30 UTCUpdated Record last modified

xmlsoft libxml2 DOWNGRADE

Affected: 2.6.0 · 2.6.1 · 2.6.2 · 2.6.3 · 2.6.4 · 2.6.5 · 2.6.6 · 2.6.7

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.6.0

1. Check installed version

apt-cache policy libxml2 || rpm -q libxml2 || libxml2 --version

2. No fixed release: DOWNGRADE to a release before 2.6.0 (Debian / Ubuntu)

apt-cache madison libxml2 sudo apt install libxml2=<VERSION_BEFORE_2.6.0> sudo apt-mark hold libxml2

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

dnf --showduplicates list libxml2 sudo dnf downgrade libxml2-<VERSION_BEFORE_2.6.0> sudo dnf versionlock add libxml2

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.

xmlsoft libxml UPGRADE

Affected: <= 1.8.16 · 1.5.0 · 1.6.0 · 1.6.1 · 1.6.2 · 1.7.0 · 1.7.1 · 1.7.2

Fixed in: newer than 1.8.16

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 1.8.16 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libxml

Note

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

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: libxmlInvalid 2.7.x - XPath Multiple Memory Corruption Vulnerabilities

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-2011-1944?

libxml2: downgrade or apply the listed mitigation; libxml: upgrade to newer than 1.8.16. Exact commands for each OS are on this page.

Is CVE-2011-1944 being exploited?

CVE-2011-1944 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-2011-1944 affect?

CVE-2011-1944 affects libxml2, libxml. Severity is high (CVSS 9.3). Integer overflow in xpath.c in libxml2 2.6.x through 2.6.32 and 2.7.x through 2.7.8, and libxml 1.8.16 and earlier, allows context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted XM

How urgent is CVE-2011-1944?

Priority 62/100. Critical severity; EPSS top 4%: very likely to be exploited; Public exploit reference

Software pages

libxml2 vulnerabilities

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References

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