CVE-2021-40509 json
ViewCommon.java in JForum2 2.7.0 allows XSS via a user signature.
published 2021-09-04 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27685
- cvss
- 5.4
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.0%
- EPSS 1.0% chance of exploitation in 30 days, percentile 61%
- public exploits
- 0
- none known
Summary
ViewCommon.java in JForum2 2.7.0 allows XSS via a user signature.
Patch / fix
- sourceforge.net/p/jforum2/code/934/ advisory
Exploit prediction
0.96% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- lists.openwall.net https://lists.openwall.net/full-disclosure/2021/09/03/7 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
| NVD | 2.0 | 3.5 | AV:N/AC:M/Au:S/C:N/I:P/A:N |
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
sourceforge.net
/p/jforum2/code/934/
patch, third-party-advisory
-
lists.openwall.net
/full-disclosure/2021/09/03/7
exploit, mailing-list, third-party-advisory
-
packetstormsecurity.com
/files/164045/jforum-2.7.0-Cross-Site-Scripting.html
third-party-advisory
-
seclists.org
/fulldisclosure/2021/Sep/13
mailing-list, third-party-advisory
Sources
- CVE List CVE-2021-40509
- NVD CVE-2021-40509
Fencer Vulns 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.