CVE-2021-27520 json
A cross-site scripting (XSS) issue in FUDForum 3.1.0 allows remote attackers to inject JavaScript via index.php in the "author" parameter.
published 2021-03-19 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-14272
- cvss
- 6.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 6.4%
- EPSS 6.4% chance of exploitation in 30 days, percentile 93%
- public exploits
- 1
- Exploit-DB, plus a Nuclei check
Summary
A cross-site scripting (XSS) issue in FUDForum 3.1.0 allows remote attackers to inject JavaScript via index.php in the "author" parameter.
Patch / fix
Timeline
- Published
- First public exploit (EDB-49943)
Exploit prediction
6.40% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- EDB-49943 FUDForum 3.1.0 - 'author' Reflected XSS webapps, 2021-06-03
- Nuclei template FUDForum 3.1.0 - Cross-Site Scripting nuclei detection template
- github.com https://github.com/fudforum/FUDforum/issues/2 referenced PoC, tagged "exploit" by a source, unverified
- packetstormsecurity.com http://packetstormsecurity.com/files/162942/FUDForum-3.1.0-Cross-Site-Scripting.html referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:N/I:P/A:N |
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
github.com
/fudforum/FUDforum/issues/2
exploit, issue-tracking, patch, third-party-advisory
-
packetstormsecurity.com
/files/162942/FUDForum-3.1.0-Cross-Site-Scripting.html
exploit, third-party-advisory, vdb-entry
Sources
- CVE List CVE-2021-27520
- NVD CVE-2021-27520
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