CVE-2003-0899Thttpd Vulnerability
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 '' characters, which trigger the overflow when the characters are expanded to "<" and…
Published Nov 3, 2003 · Updated Apr 15, 2026
Key Facts
Patch immediately- CVE-2003-0899 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Thttpd (Acme).
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 22% probability of exploitation in the next 30 days.
- Fixed versions are available, including Thttpd 2.23, Thttpd 2.21b-11.2.
- Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Scores
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
22%
Higher than 97.6% of all scored CVEs
Exploit maturity
Proof of concept
ATLAS score
41/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Not listed
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Proof of concept
Public exploit code
2
Proof-of-concept links
In-the-wild evidence
1
Reports of active use
Advisories And Exploit References
- advisorythttpd-defang-bo(13530)
- patch10092
- patch8906
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 '' characters, which trigger the overflow when the characters are expanded to "" sequences.
Affected Products
4 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| ThttpdAcme | 2.23, 2.23-b1 | 2.23 |
Patched Releases
Thttpd
2.23, 2.21b-11.2
Timeline
Publicly disclosed
Nov 3, 2003
Last updated
Apr 15, 2026
Weakness Type
- CWE-131 Incorrect Calculation of Buffer Size
References
- advisorythttpd-defang-bo(13530)
- patch10092
- patch8906
- exploit20031027 Remote overflow in thttpd
- exploitExploitDB-23305
FAQ
Common Questions.
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 '' characters, which trigger the overflow when the characters are expanded to "" sequences.
Affected: Thttpd (Acme) versions 2.23, 2.23-b1. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Thttpd 2.23, Thttpd 2.21b-11.2.
Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Is CVE-2003-0899 On Your Attack Surface?
Brandefense matches it against the products discovered on your perimeter and opens a finding the day a CVE like this is listed.
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