What is CVE-2020-17496?

CVE-2020-17496 is a critical-severity vulnerability in Vbulletin, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 9.8/10. Published 2020-08-12.

How severe is CVE-2020-17496?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2020-17496 known to be exploited?

Yes. CVE-2020-17496 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 20 public proof-of-concept repositories are indexed.

Vulnerability in Vbulletin

CVE-2020-17496

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 2020-08-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.875 (99.8th percentile), scored 2026-10-16.

High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.877 · newest: 0.875 · change: -0.003

Affected products

Vbulletin

Weakness classification (CWE)

CWE-74 — Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection)

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2021-11-03. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-05-03.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

cwe.mitre.org/data/definitions/78.html (Technical Description)
blog.exploitee.rs/2020/exploiting-vbulletin-a-tale-of-patch-fail/ (Exploit, Third Party Advisory)
forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-announcements_aa/44… (Patch, Vendor Advisory)
seclists.org/fulldisclosure/2020/Aug/5 (Exploit, Mailing List, Third Party Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2020-17496?: CVE-2020-17496 is a critical-severity vulnerability in Vbulletin, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 9.8/10. Published 2020-08-12.
How severe is CVE-2020-17496?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2020-17496 known to be exploited?: Yes. CVE-2020-17496 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 20 public proof-of-concept repositories are indexed.