CVE-2009-2416: Multiple use-after-free vulnerabilities in libxml2 2.5.10, 2.6.16, 2.6.26, 2.6.27, and 2.6.32, and libxml 1.8.

This month

MEDIUM 6.5WATCHLISTDOWNGRADEDOWNGRADEMITIGATE

CVE-2009-2416 is a medium-severity flaw (CVSS 6.5) affecting libxml, libxml2, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Multiple use-after-free vulnerabilities in libxml2 2.5.10, 2.6.16, 2.6.26, 2.6.27, and 2.6.32, and libxml 1.8.17, allow context-dependent attackers to cause a denial of service (application crash) via crafted (1) Notation or (2) Enumeration attribute types in an XML file, as demonstrated by the Codenomicon XML fuzzing framework.

Why this priority

On your watchlist

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

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	2.0% (top 20%)
CISA exploited list	No
Weakness	CWE-416
Published	2009-08-11
Last modified	2026-06-16

Publisher (CNA): Red Hat, Inc. · Vendor: canonical · debian · fedoraproject · redhat · xmlsoft

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

Am I affected?

Timeline

2009-08-11 18:30 UTCPublished CVE record published
2026-06-16 23:09 UTCUpdated Record last modified

xmlsoft libxml DOWNGRADE

Affected: 1.8.17

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.8.17

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.8.17 (Debian / Ubuntu)

apt-cache madison libxml sudo apt install libxml=<VERSION_BEFORE_1.8.17> sudo apt-mark hold libxml

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

dnf --showduplicates list libxml sudo dnf downgrade libxml-<VERSION_BEFORE_1.8.17> sudo dnf versionlock add libxml

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 libxml2 DOWNGRADE

Affected: 2.5.10 · 2.6.16 · 2.6.26 · 2.6.27 · 2.6.32

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.5.10

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.5.10 (Debian / Ubuntu)

apt-cache madison libxml2 sudo apt install libxml2=<VERSION_BEFORE_2.5.10> sudo apt-mark hold libxml2

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

dnf --showduplicates list libxml2 sudo dnf downgrade libxml2-<VERSION_BEFORE_2.5.10> 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.

fedoraproject fedora MITIGATE

Affected: 10 · 11

Fixed in: no fixed release known

Safe to downgrade to: a release before 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.

debian debian linux MITIGATE

Affected: 4.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.0

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.

redhat enterprise linux MITIGATE

Affected: 3.0 · 4.0 · 5.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.0

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.

canonical ubuntu linux MITIGATE

Affected: 6.06 · 8.04 · 8.10 · 9.04

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.06

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-2009-2416?

libxml: downgrade or apply the listed mitigation; libxml2: downgrade or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2009-2416 being exploited?

CVE-2009-2416 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-2009-2416 affect?

CVE-2009-2416 affects libxml, libxml2, fedora. Severity is medium (CVSS 6.5). Multiple use-after-free vulnerabilities in libxml2 2.5.10, 2.6.16, 2.6.26, 2.6.27, and 2.6.32, and libxml 1.8.17, allow context-dependent attackers to cause a denial of service (application crash) via crafted (1) Notation or (2) Enumeration

How urgent is CVE-2009-2416?

Priority 48/100. On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities · libxml2 vulnerabilities

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References

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