CVE-2020-17496
CVE-2020-17496 — vBulletin PHP Module Remote Code Execution Vulnerability
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.
Published Updated Sources: NVD, CISA, FIRST EPSS
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Confirmed
CISA KEV, listed Nov 3, 2021
EPSS
88%
ahead of 99.8% of scored CVEs
CVSS base
9.8
critical · 2 sources
CISA SSVC assessment
Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.
Exploitation
Active
none · proof-of-concept · active
Automatable
Yes
can an attacker script all four kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component
Remediation
The vendor's own words where we have them.
Upgrade vBulletin to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.
CISA required action
Apply updates per vendor instructions.
Federal deadline May 3, 2022 — passed 1,581 days ago
First 24 hours
Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.
- Identify exposed assets running affected vendor/product/version combinations.
- Treat as emergency remediation because CISA KEV status is present.
- Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.
Affected scope
Vendor, product and version as the advisories word them.
| Vendor | Product | Versions | Status |
|---|---|---|---|
| vBulletin | vBulletin | — | Vulnerable |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Availability
High
Confidentiality
High
Integrity
High
Scope
Unchanged
Attack Complexity
Low
Attack Vector
Network
Privileges Req
None
User Interaction
None
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 9.8 | CVSS 3.1 | critical | 3.9 | 5.9 | NVD, CNA |
| 7.5 | CVSS 2.0 | high | 10 | 6.4 | NVD |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness & attack patterns
- CWE-74Injection
Inferred from the weakness class — not observed against this CVE.
- T1562.003Impair Defenses: Impair Command History Logging
- T1574.006Hijack Execution Flow: Dynamic Linker Hijacking
- T1574.007Hijack Execution Flow: Path Interception by PATH Environment Variable
CISA KEV details
CISA lists a CVE here once it has evidence of exploitation against real targets.
Listed
Nov 3, 2021
Federal deadline
May 3, 2022
passed 1,581 days ago
Ransomware use
Unknown
CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.
Public exploit
Capability, not use: code existing is a different claim from anyone running it.
Exploit entries
1
Exploit-DB and CTI exploit indexes
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Search application, proxy, and WAF logs for requests touching /render/widget_tabbedcontainer_tab_panel.
- Prioritize edge telemetry for network-reachable vBulletin.
- Monitor for scanner or exploit-pattern traffic after 1 public PoC repositories were reported.
Timeline
What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.
- 2026
Added · CVSS 3.1 9.8 (AV:N)
Jun 17, 2026 · NVD
- 2021
Added to CISA KEV catalog
Nov 3, 2021 · CISA
- 2020
Initial · CVE published
Aug 12, 2020 · NVD
References
6 on the record
- blog.exploitee.rs/2020/exploiting-vbulletin-a-tale-of-patch-fail/
Exploit, Third Party Advisory
- cwe.mitre.org/data/definitions/78.html
Technical Description
- 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
- seclists.org/fulldisclosure/2020/Aug/5
Exploit, Mailing List, Third Party Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-17496
US Government Resource
- nvd.nist.gov/vuln/detail/CVE-2020-17496
Vendor Advisory
Elsewhere on this site
- vBulletinevery CVE for this vendor
- November 2021what else CISA listed
- Injectionsame class
- CWE-74other pages naming this weakness
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1
What should defenders know first?
CVE-2020-17496 is vBulletin PHP Module Remote Code Execution Vulnerability, a critical vulnerability affecting vBulletin from vBulletin. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 1 public PoC repositories reported; 0 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 9.8 describes technical severity, while EPSS 88% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.