CVE-2008-0555: The ExpandCert function in Apache-SSL before apache_1.3.41+ssl_1.59 does not properly handle (1) '/' and (2) '

This month

HIGH 7.5WATCHLISTDOWNGRADE

CVE-2008-0555 is a high-severity flaw (CVSS 7.5) affecting apache-ssl. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The ExpandCert function in Apache-SSL before apache_1.3.41+ssl_1.59 does not properly handle (1) '/' and (2) '=' characters in a Distinguished Name (DN) in a client certificate, which might allow remote attackers to bypass authentication via a crafted DN that triggers overwriting of environment variables.

Why this priority

High severity
Public exploit reference
On your watchlist

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	1.9% (top 21%)
CISA exploited list	No
Weakness	CWE-20, CWE-287
Published	2008-04-04
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: apache-ssl

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

Am I affected?

Timeline

2008-04-04 00:44 UTCPublished CVE record published
2026-06-16 22:49 UTCUpdated Record last modified

apache-ssl apache-ssl DOWNGRADE

Affected: 1.3.34_1.57

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.3.34_1.57

1. Check installed version

apt-cache policy apache-ssl || rpm -q apache-ssl || apache-ssl --version

2. No fixed release: DOWNGRADE to a release before 1.3.34_1.57 (Debian / Ubuntu)

apt-cache madison apache-ssl sudo apt install apache-ssl=<VERSION_BEFORE_1.3.34_1.57> sudo apt-mark hold apache-ssl

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

dnf --showduplicates list apache-ssl sudo dnf downgrade apache-ssl-<VERSION_BEFORE_1.3.34_1.57> sudo dnf versionlock add apache-ssl

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-2008-0555?

apache-ssl: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2008-0555 being exploited?

CVE-2008-0555 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-2008-0555 affect?

CVE-2008-0555 affects apache-ssl. Severity is high (CVSS 7.5). The ExpandCert function in Apache-SSL before apache_1.3.41+ssl_1.59 does not properly handle (1) '/' and (2) '=' characters in a Distinguished Name (DN) in a client certificate, which might allow remote attackers to bypass authentication vi

How urgent is CVE-2008-0555?

Priority 56/100. High severity; Public exploit reference; On your watchlist

Related CVEs

CVE-2004-0009 HIGH 7.5 UPGRADE Apache-SSL 1.3.28+1.52 and earlier, with SSLVerifyClient set to 1 or 3 and SSLFakeBasicAuth enabled, allows re
CVE-2002-0082 HIGH 7.5 DOWNGRADE DOWNGRADE The dbm and shm session cache code in mod_ssl before 2.8.7-1.3.23, and Apache-SSL before 1.3.22+1.46, does not

References

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