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Fencer Intel
critical 9.8

CVE-2009-4491 in the critical feed json

thttpd 2.25b0 writes data to a log file without sanitizing non-printable characters, which might allow remote attackers to modify a window'…

published 16y ago modified 4mo ago also EUVD-2009-4458

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
13.7%
EPSS 13.7% chance of exploitation in 30 days, percentile 96%
public exploits
1
Exploit-DB

Summary

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.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2009-4491 updated

thttpd log file sanitization flaw

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Timeline

  1. First public exploit (EDB-33499)
  2. Published

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
2y ago

Exploit prediction

13.72% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • EDB-33499 thttpd 2.24 - HTTP Request Escape Sequence Terminal Command Injection remote, 2010-01-11
  • ush.it http://www.ush.it/team/ush/hack_httpd_escape/adv.txt referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N

Affected products

  • thttpd thttpd_http_server

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code
  • CWE-20 Improper Input Validation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.