Acme Labs thttpd up to 2.20b Basic Authentication off-by-one

CVSS Meta Temp Score
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CTI Interest Score
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7.0$0-$5k0.00

Summaryinfo

A vulnerability was found in Acme Labs thttpd. It has been rated as critical. The affected element is an unknown function of the component Basic Authentication Handler. This manipulation causes off-by-one. This vulnerability is registered as CVE-2001-1496. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in Acme Labs thttpd (Web Server) and classified as critical. Affected by this vulnerability is an unknown function of the component Basic Authentication Handler. The manipulation with an unknown input leads to a off-by-one vulnerability. The CWE definition for the vulnerability is CWE-193. A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Off-by-one buffer overflow in Basic Authentication in Acme Labs thttpd 1.95 through 2.20 allows remote attackers to cause a denial of service and possibly execute arbitrary code.

The weakness was published 12/31/2001 by Gobbles (Website). It is possible to read the advisory at securityfocus.com. This vulnerability is known as CVE-2001-1496 since 06/21/2005. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available.

The commercial vulnerability scanner Qualys is able to test this issue with plugin 86279 (Acme THTTPd Basic Authentication Buffer Overflow Vulnerability).

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at X-Force (7595), SecurityFocus (BID 3562†) and Vulnerability Center (SBV-6145†). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Off-by-one
CWE: CWE-193 / CWE-189
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Timelineinfo

11/20/2001 🔍
11/20/2001 +0 days 🔍
12/31/2001 +41 days 🔍
12/31/2001 +0 days 🔍
11/25/2004 +1060 days 🔍
06/21/2005 +208 days 🔍
07/11/2014 +3307 days 🔍
09/24/2025 +4093 days 🔍

Sourcesinfo

Advisory: securityfocus.com⛔
Researcher: Gobbles
Status: Confirmed

CVE: CVE-2001-1496 (🔍)
GCVE (CVE): GCVE-0-2001-1496
GCVE (VulDB): GCVE-100-17815
X-Force: 7595
SecurityFocus: 3562 - thttpd Basic Authentication Buffer Overflow Vulnerability
Vulnerability Center: 6145 - DoS in Thttpd via Buffer Overflow, High

Entryinfo

Created: 07/11/2014 13:26
Updated: 09/24/2025 21:38
Changes: 07/11/2014 13:26 (57), 05/26/2019 19:04 (3), 09/24/2025 21:38 (20)
Complete: 🔍
Cache ID: 216:DE9:103

Be aware that VulDB is the high quality source for vulnerability data.

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