vBulletin 5.5.4 through 5.6.2 allows remote command execution via crafted subWidgets data in an ajax/render/widget_tabbedcontainer_tab_panel request. NOTE: this issue exists because of an incomplete fix for CVE-2019-16759.
Conclusion & alert: CVE-2020-17496 is rated Critical Active Threat (94.1/100): CVSS Critical severity, with high exploitation likelihood (EPSS 87.74%, 100th percentile). Core evidence: CISA KEV confirms active exploitation (added 2021-11-03) affecting vBulletin / vBulletin. a weakness (CWE-74) Unauthenticated remote administrative access may be possible. Mandatory action: The CISA remediation deadline has passed—treat as an emergency patch priority.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
: vBulletin PHP Module Remote Code Execution Vulnerability · CISA KEV detail
: 2021-11-03
: 2022-05-03
: Apply updates per vendor instructions.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ | |
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 94.22% | 87.74% | -6.48% |
| 2 | 2026-01-16 | 94.04% | 94.22% | +0.19% |
| 3 | 2025-07-02 | — | 94.04% | — |
Full EPSS history (15 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.1 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| 9.8 | 3.1 | CRITICAL |
|
3.9 | 5.9 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| 7.5 | 2.0 | HIGH |
|
10.0 | 6.4 | [email protected] |
| URL | Tags |
|---|---|
| https://blog.exploitee.rs/2020/exploiting-vbulletin-a-tale-of-patch-fail/ | Exploit Third Party Advisory |
| https://cwe.mitre.org/data/definitions/78.html | Technical Description |
| https://forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-announcements_aa/4445227-vbulletin-5-6-0-5-6-1-5-6-2-security-patch | Patch Vendor Advisory |
| https://seclists.org/fulldisclosure/2020/Aug/5 | Exploit Mailing List Third Party Advisory |
| https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-17496 | US Government Resource |