No exploitation reportedFix available

CVE-2003-0899

Q: Is CVE-2003-0899 actively exploited?

Active exploitation of CVE-2003-0899 has not been confirmed. Its EPSS score was 22.2% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2003-0899?

CVE-2003-0899 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2003-11-03
Fixed in2.23
WeaknessCWE-131

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Buffer overflow in defang in libhttpd.c for thttpd 2.21 to 2.23b1 allows remote attackers to execute arbitrary code via requests that contain '<' or '>' characters, which trigger the overflow when the characters are expanded to "<" and ">" sequences.

Timeline

dates in UTC

2003-11-0305:00CVE publishedNVD
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2003-0899?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2003-0899?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Acme thttpd

Branch	Affected	Fixed in	Source
2.x	≥ 2.21, < 2.23	2.23	NVD
2.23	= 2.23	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Acme thttpd to 2.23

Advisories and patches

secunia.comPatch · Vendor Advisory
www.securityfocus.comPatch

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.19.8read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
NVDweakness (CWE)CWE-131read 2026-10-23
FIRST EPSSEPSS score22.2 %read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2003-11-03
Last Modified: 2026-06-16
NVD status: Modified

Frequently asked questions

What is CVE-2003-0899?

Is CVE-2003-0899 actively exploited?

Active exploitation of CVE-2003-0899 has not been confirmed. Its EPSS score was 22.2% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2003-0899?

CVE-2003-0899 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Hear about the next vulnerability in your software

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this product CISA KEV additions, October 2026 Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.

Other 2003 vulnerabilities worth triaging

Ranked by exploit probability (EPSS).

Back to CVE Database