CVE-2021-39345 json
HAL <= 2.1.1 Authenticated Stored Cross-Site Scripting
published 2021-10-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-25706
- cvss
- 5.5
- version 3.1, CNA
- 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
The HAL WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and sanitization via several parameters found in the ~/wp-hal.php file which allowed attackers with administrative user access to inject arbitrary web scripts, in versions up to and including 2.1.1. This affects multi-site installations where unfiltered_html is disabled for administrators, and sites where unfiltered_html is disabled.
Patch / fix
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 19 mo ago
Exploit prediction
0.95% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/BigTiger2020/word-press/blob/main/HAL.md referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.5 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N |
| NVD | 3.1 | 4.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N |
| NVD | 2.0 | 2.1 | AV:N/AC:H/Au:S/C:N/I:P/A:N |
Affected products
- HAL HAL
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
- Technology feeds
References
-
plugins.trac.wordpress.org
/changeset?sfp_email=&sfph_mail=&reponame=&old=2614075%40hal&new=2614075%40hal&sfp_email=&sfph_mail=
patch, third-party-advisory
-
github.com
/BigTiger2020/word-press/blob/main/HAL.md
exploit, third-party-advisory
-
wordfence.com
/vulnerability-advisories/#CVE-2021-39345
third-party-advisory
Sources
- CVE List CVE-2021-39345
- NVD CVE-2021-39345
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.