Account takeover via script-readable session cookie
Published May 7, 2026 · Updated May 7, 2026
Sensitive cookie handling in Budibase before 3.35.10 allows context-dependent attackers to steal session tokens through injected JavaScript. The cookie setter in packages/backend-core/src/utils/utils.ts writes the budibase:auth JWT cookie with httpOnly disabled and omits Secure and SameSite, exposing it to document.cookie and plaintext HTTP. Successful exploitation requires JavaScript execution in a victim's browser, such as through XSS, and grants persistent access with the victim's account privileges.
Summary
What happened
Sensitive cookie handling in Budibase before 3.35.10 allows context-dependent attackers to steal session tokens through injected JavaScript. The cookie setter in packages/backend-core/src/utils/utils.ts writes the budibase:auth JWT cookie with httpOnly disabled and omits Secure and SameSite, exposing it to document.cookie and plaintext HTTP. Successful exploitation requires JavaScript execution in a victim's browser, such as through XSS, and grants persistent access with the victim's account privileges.
The record
- CVE
- CVE-2026-42239
- Published
- May 7, 2026
- Updated
- May 7, 2026
- Vendor
- Budibase
- Product
- Budibase
- Classifications
- CWE-1004, T1539
- Attack vector
- network
- Privileges
- Unavailable
Timeline
How it unfolded
- May 7, 2026CVE publishedPublication date reported by the CVE source.
- May 7, 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.
- Affected versionversion=< 3.35.10
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- Session-cookie theft proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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