CVE-2000-0900: Directory traversal vulnerability in ssi CGI program in thttpd 2.19 and earlier allows remote attackers to rea

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HIGH 7.5DOWNGRADE

CVE-2000-0900 is a high-severity flaw (CVSS 7.5) affecting thttpd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Directory traversal vulnerability in ssi CGI program in thttpd 2.19 and earlier allows remote attackers to read arbitrary files via a "%2e%2e" string, a variation of the .. (dot dot) attack.

Why this priority

High severity
Public exploit reference

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	2.0% (top 19%)
CISA exploited list	No
Published	2000-12-19
Last modified	2026-09-23

Publisher (CNA): MITRE · Vendor: acme labs

Last updated 2026-09-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2000-12-19 05:00 UTCPublished CVE record published
2026-09-23 09:10 UTCUpdated Record last modified

acme labs thttpd DOWNGRADE

Affected: 2.16 · 2.17 · 2.18 · 2.19

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.16

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.16 (Debian / Ubuntu)

apt-cache madison thttpd sudo apt install thttpd=<VERSION_BEFORE_2.16> sudo apt-mark hold thttpd

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

dnf --showduplicates list thttpd sudo dnf downgrade thttpd-<VERSION_BEFORE_2.16> sudo dnf versionlock add thttpd

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-2000-0900?

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

Is CVE-2000-0900 being exploited?

CVE-2000-0900 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-2000-0900 affect?

CVE-2000-0900 affects thttpd. Severity is high (CVSS 7.5). Directory traversal vulnerability in ssi CGI program in thttpd 2.19 and earlier allows remote attackers to read arbitrary files via a "%2e%2e" string, a variation of the .. (dot dot) attack.

How urgent is CVE-2000-0900?

Priority 51/100. High severity; Public exploit reference

Related CVEs

CVE-2017-17663 CRITICAL 9.8 UPGRADE UPGRADE The htpasswd implementation of mini_httpd before v1.28 and of thttpd before v2.28 is affected by a buffer over
CVE-2013-0348 LOW 2.1 UPGRADE MITIGATE thttpd.c in sthttpd before 2.26.4-r2 and thttpd 2.25b use world-readable permissions for /var/log/thttpd.log,
CVE-2012-5640 MEDIUM 5.5 MITIGATE thttpd has a local DoS vulnerability via specially-crafted .htpasswd files
CVE-2009-4491 CRITICAL 9.8 DOWNGRADE thttpd 2.25b0 writes data to a log file without sanitizing non-printable characters, which might allow remote
CVE-2007-0664 MEDIUM 5.0 UPGRADE thttpd before 2.25b-r6 in Gentoo Linux is started from the system root directory (/) by the Gentoo baselayout

References

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