CVE-2009-2474: neon before 0.28.6, when OpenSSL or GnuTLS is used, does not properly handle a '\0' character in a domain name

Q: How do I fix CVE-2009-2474?

neon: upgrade to 0.28.6; mac os x: upgrade to 10.6.5; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2009-2474 being exploited?

CVE-2009-2474 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-2009-2474 affect?

CVE-2009-2474 affects neon, mac os x, ubuntu linux. Severity is medium (CVSS 5.8). neon before 0.28.6, when OpenSSL or GnuTLS is used, does not properly handle a '\0' character in a domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL

Q: How urgent is CVE-2009-2474?

Priority 44/100. On your watchlist

This month

MEDIUM 5.8WATCHLISTUPGRADEUPGRADEMITIGATE

CVE-2009-2474 is a medium-severity flaw (CVSS 5.8) affecting neon, mac os x, ubuntu linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

neon before 0.28.6, when OpenSSL or GnuTLS is used, does not properly handle a '\0' character in a domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.8 (Medium)
EPSS exploit chance	1.5% (top 26%)
CISA exploited list	No
Weakness	CWE-326
Published	2009-08-21
Last modified	2026-06-16

Publisher (CNA): Red Hat, Inc. · Vendor: apple · canonical · fedoraproject · webdav

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

Am I affected?

Timeline

2009-08-21 17:30 UTCPublished CVE record published
2026-06-16 23:09 UTCUpdated Record last modified

webdav neon UPGRADE

Affected: < 0.28.6

Fixed in: 0.28.6

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 0.28.6 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade neon

Note

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

apple mac os x UPGRADE

Affected: < 10.6.5

Fixed in: 10.6.5

Safe to downgrade to: no unaffected older release

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.

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.

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-2009-2474?

neon: upgrade to 0.28.6; mac os x: upgrade to 10.6.5; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2009-2474 being exploited?

CVE-2009-2474 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-2009-2474 affect?

CVE-2009-2474 affects neon, mac os x, ubuntu linux. Severity is medium (CVSS 5.8). neon before 0.28.6, when OpenSSL or GnuTLS is used, does not properly handle a '\0' character in a domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL

How urgent is CVE-2009-2474?

Priority 44/100. On your watchlist

Software pages

OpenSSL vulnerabilities · Ubuntu vulnerabilities · GnuTLS vulnerabilities

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References

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