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Vulnerability record · CVE-2009-4491 · published 13 January 2010

CVE-2009-4491: Acme thttpd improper input validation vulnerability

Acme · Thttpd

thttpd 2.25b0 writes data to a log file without sanitizing non-printable characters, which might allow remote attackers to modify a window's title, or possibly execute arbitrary commands or overwrite files, via an HTTP request containing an escape sequence for a terminal emulator.

9.8 CVSS 3.1 Critical EPSS 14% · top 3.6% CWE-20 · Improper input validationCWE-94 · Code injection
9.8CVSS 3.1 base score, v2 5.0
14%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References, 2 tagged exploit
16 Jun 2026Last modified by NVD

Description

thttpd 2.25b0 writes data to a log file without sanitizing non-printable characters, which might allow remote attackers to modify a window's title, or possibly execute arbitrary commands or overwrite files, via an HTTP request containing an escape sequence for a terminal emulator.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://packetstormsecurity.com/files/175949/m-privacy-TightGate-Pro-Code-Execution-Insecure-Permissions.html
http://seclists.org/fulldisclosure/2023/Nov/13
http://www.securityfocus.com/archive/1/508830/100/0/threaded
http://www.ush.it/team/ush/hack_httpd_escape/adv.txt Exploit
http://packetstormsecurity.com/files/175949/m-privacy-TightGate-Pro-Code-Execution-Insecure-Permissions.html
http://seclists.org/fulldisclosure/2023/Nov/13
http://www.securityfocus.com/archive/1/508830/100/0/threaded
http://www.ush.it/team/ush/hack_httpd_escape/adv.txt Exploit

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2007-0158Acme thttpd out-of-bounds write vulnerabilitythttpd 2007 has buffer underflow.EPSS 1.3%9.8CVE-2017-17663Acme mini httpd memory buffer overflow vulnerabilityThe htpasswd implementation of mini_httpd before v1.28 and of thttpd before v2.28 is affected by a buffer overflow that can be exploited remotely to …EPSS 2.7%9.8CVE-2003-0899Acme thttpd vulnerabilityBuffer 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 …EPSS 22%9.8CVE-2001-1496Acme thttpd vulnerabilityOff-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 pos…EPSS 4.8%5.5CVE-2012-5640Acme thttpd null pointer dereference vulnerabilitythttpd has a local DoS vulnerability via specially-crafted .htpasswd filesEPSS 0.39%5.0CVE-2001-0892Acme thttpd exposure of resource to wrong sphere vulnerabilityAcme Thttpd Secure Webserver before 2.22, with the chroot option enabled, allows remote attackers to view sensitive files under the document root (su…EPSS 1.9%2.1CVE-2013-0348Open source development team sthttpd permissions and access controls vulnerabilitythttpd.c in sthttpd before 2.26.4-r2 and thttpd 2.25b use world-readable permissions for /var/log/thttpd.log, which allows local users to obtain sens…EPSS 0.52%9.5CVE-2026-93952Arista velocloud orchestrator improper input validation vulnerabilityVeloCloud Orchestrator (VCO) on-prem has a security issue where this issue may allow a remote attacker to access privileged internal functionality an…KEVEPSS 0.90%

Source: NIST National Vulnerability Database (record CVE-2009-4491), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.