CVE-2020-17496Known exploitationPublic exploitNetwork attack vector

Unauthenticated code execution via nested PHP widgets

Published Aug 12, 2020 · Updated Oct 21, 2025

Code injection in vBulletin 5.5.4 through 5.6.2 allows remote attackers to execute commands via Ajax widget rendering. The widget_tabbedcontainer_tab_panel template accepts attacker-controlled subWidgets, loads widget_php as a child, and copies its config into widgetConfig, bypassing the earlier filtering before PHP evaluation. Exploitation requires reachable Ajax rendering and enabled PHP widgets, but no authentication or user interaction; execution inherits the web application's permissions.

CVSS severity9.8
Critical
EPSS probability87.48%
Next 30 days · Nov 1, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in vBulletin 5.5.4 through 5.6.2 allows remote attackers to execute commands via Ajax widget rendering. The widget_tabbedcontainer_tab_panel template accepts attacker-controlled subWidgets, loads widget_php as a child, and copies its config into widgetConfig, bypassing the earlier filtering before PHP evaluation. Exploitation requires reachable Ajax rendering and enabled PHP widgets, but no authentication or user interaction; execution inherits the web application's permissions.

The record

CVE
CVE-2020-17496
Published
Aug 12, 2020
Updated
Oct 21, 2025
Vendor
vBulletin
Product
vBulletin
Classifications
CWE-74, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 10, 2020Exploitation reportedUnit 42 observed exploitation
  2. Aug 12, 2020CVE publishedPublication date reported by the CVE source.
  3. Oct 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

vBulletin · vBulletinversion=n/a

Published CVSS scores

9.8CISA ADP VulnrichmentCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsShadowserver observations through Sep 28, 2026. Gaps indicate unavailable data.
Sep 22, 2026Sep 28, 2026
View daily counts
Reporting dayUnique IPs
Sep 22, 202610
Sep 23, 20264
Sep 24, 202618
Sep 25, 202619
Sep 26, 20265
Sep 27, 202617
Sep 28, 202610
Latest reporting daySep 28, 2026
Latest daily unique IPs10
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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