How severe is CVE-2020-17496?

CVE-2020-17496 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which products are affected by CVE-2020-17496?

CVE-2020-17496 affects the following products: vbulletin vbulletin.

How do I patch CVE-2020-17496?

No patch has shipped for CVE-2020-17496 yet — track the vbulletin vbulletin advisory for a fixed release and apply the workarounds below in the meantime.

How do I detect CVE-2020-17496 across my infrastructure?

Inventory every vbulletin vbulletin deployment and check each version against the affected-products list above.

How do I mitigate CVE-2020-17496 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Is CVE-2020-17496 actively exploited in the wild?

Yes. There are 6 known exploit references for CVE-2020-17496, including 5 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2020-17496?

CVE-2020-17496 has an EPSS (Exploit Prediction Scoring System) score of 87.5%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2020-17496 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2020-17496 (vBulletin PHP Module Remote Code Execution Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2021-11-03. CISA required all US federal civilian agencies to remediate this vulnerability by 2022-05-03. The required action was: Apply updates per vendor instructions. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2020-17496?

CVE-2020-17496 is classified as CWE-74 (CWE-74). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2020-17496?

CVE-2020-17496 affects vbulletin vbulletin. Check the affected-products list on this page against your deployed version to confirm exposure.

Is there exploit tooling available for CVE-2020-17496?

A Nuclei detection template exists for CVE-2020-17496, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2020-17496 published, and has it been updated?

CVE-2020-17496 was published on August 12, 2020 and was last updated on June 17, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🛡️

CISA KEV · ACTIVELY EXPLOITED

CRITICAL severity

CVE-2020-17496 — Vbulletin

CRITICAL

CVE-2020-17496 is a critical-severity (CVSS 9.8) CWE-74 vulnerability in vbulletin vbulletin. It is in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.

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…

Published

Aug 12, 2020

Updated

Jun 17, 2026

Affected

1 product

Patched

See advisory

Exploits

6 known

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2021-11-03. Federal agencies were required to remediate by 2022-05-03.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2020-17496.

EPSS Exploitation Probability

via FIRST.org ↗

87.5%probability of exploitation in next 30 days

Very High Risk+0.11%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2020-17496 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).

Where this sits among everything scored

Of 395,249 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Counts from FIRST.org, log-scaled.

Description

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.

Affected Products

1 product · 1 configurations

Application

vbulletinvbulletin

≥ 5.5.4 && ≤ 5.6.2

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.