CVE-2009-4491

Exp

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.

Published: 2010-01-13 Last update: 2026-04-23 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2009-4491 is rated High Exploit Risk (92.8/100): CVSS Critical severity, with high exploitation likelihood (EPSS 13.36%, 96th percentile). 2 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +10.65% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2009-4491

EDB-ID Source Kind Published Link
33499 exploit_db edb 2010-01-11 Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2009-4491

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 2.71% 13.36% +10.65%
2 2025-12-28 4.02% 2.71% -1.30%
3 2025-12-27 — 4.02% —

Full EPSS history (20 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2009-4491

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2009-4491

OS Trackers for CVE-2009-4491

vendor priority summary link
ubuntu negligible CVE-2009-4491 negligible priority: Ubuntu including 1 source packages (thttpd), 14 status rows across 14 suites (dapper, hardy, intrepid, jaunty, karmic, lucid, maverick, natty, oneiric, precise, quantal, raring, saucy, upstream): ignored 9, DNE 4, needs-triage 1. https://ubuntu.com/security/CVE-2009-4491

Affected software / configurations for CVE-2009-4491

Vendor Product Version Raw CPE
acme thttpd 2.25 cpe:2.3:a:acme:thttpd:2.25:b:*:*:*:*:*:*

References for CVE-2009-4491

cvelogic Threat Intelligence