cve.bz

CVE-2026-121763 wpmu dev hummingbird: Cross-site Scripting

6.5 mediumEPSS 0.2%Fix available

Medium (6.5) in wpmu dev hummingbird. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.

On this page
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in WPMU DEV Hummingbird hummingbird-performance allows Stored XSS.This issue affects Hummingbird: from n/a through 3.21.2.

Severity

CVSS 3.1

6.5 medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
EPSS
0.2% estimated probability of exploitation activity in the next 30 days; 6th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
CISA's assessment (SSVC)
Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-09. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
CWE
CWE-79 Improper Neutralization of Input During Web Page Generation (Cross-site Scripting)
OWASP Top 10
A05:2025 Injection
Published
Modified
NVD analysis
Deferred: the NVD does not plan to analyze it
Record from
the NVD, synced

Ask an AI about this CVE

ChatGPTClaudeGoogle AI Mode

Show the promptExplain CVE-2026-121763 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-121763?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-121763?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-121763 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.

Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.

Badge for a README or a site

CVE-2026-121763

An image that stays current: it is drawn from the data each time it is fetched (a host that proxies images, as GitHub does, may show its copy for a while). Markdown:

[![CVE-2026-121763](https://cve.bz/cve/badge/CVE-2026-121763.svg)](https://cve.bz/cve/CVE-2026-121763)

HTML:

<a href="https://cve.bz/cve/CVE-2026-121763"><img src="https://cve.bz/cve/badge/CVE-2026-121763.svg" alt="CVE-2026-121763"></a>

Affected

  • wpmu dev:hummingbird

Versions

From the CNA's record in the CVE List.

ProductAffected
WPMU DEV Hummingbirdthrough 3.21.2

Fixed in

ProductFixed in
WPMU DEV Hummingbird4.0.0

Fix and patched versions

  • WPMU DEV Hummingbird: fixed in 4.0.0

Attack patterns (CAPEC)

  • CAPEC-63 Cross-Site Scripting (XSS) Likelihood: High · Severity: Very High
  • CAPEC-85 AJAX Footprinting Likelihood: High · Severity: Low
  • CAPEC-209 XSS Using MIME Type Mismatch Severity: Medium
  • CAPEC-588 DOM-Based XSS Likelihood: High · Severity: Very High
  • CAPEC-591 Reflected XSS Likelihood: High · Severity: Very High
  • CAPEC-592 Stored XSS Likelihood: High · Severity: Very High

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

References

Check your stackJSON