CVE-2026-46426Public exploitNetwork attack vector

Stored XSS via conditional active-content filtering

Published May 27, 2026 · Updated May 27, 2026

Stored XSS in self-hosted Budibase before 3.38.2 allows remote authenticated users to run JavaScript in app users' browsers via uploads. The shared uploadFile handler applies dangerous-extension checks only to public users or non-self-hosted deployments, then stores active content with executable MIME types. A builder, or an app user with table-write permission, must upload the file and another app user must open its signed URL, enabling session theft or account takeover.

CVSS severity7.6
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in self-hosted Budibase before 3.38.2 allows remote authenticated users to run JavaScript in app users' browsers via uploads. The shared uploadFile handler applies dangerous-extension checks only to public users or non-self-hosted deployments, then stores active content with executable MIME types. A builder, or an app user with table-write permission, must upload the file and another app user must open its signed URL, enabling session theft or account takeover.

The record

CVE
CVE-2026-46426
Published
May 27, 2026
Updated
May 27, 2026
Vendor
Budibase
Product
Budibase
Classifications
CWE-434, CWE-79, T1185
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 2026Record 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=< 3.38.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Budibase · Budibaseversion=< 3.38.2

Published CVSS scores

7.6BudibaseCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1185Browser Session Cookie

Public exploit references

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

Technologies

Your stack

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Your stack

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