CVE-2026-42239 json
Budibase auth session cookies are set with httpOnly:false — any XSS can lead to full account takeover
published 2026-04-24 6 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-28429 , GHSA-4f9j-vr4p-642r
- cvss
- 8.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 21%
- public exploits
- 0
- none known
Summary
Budibase is an open-source low-code platform. Prior to version 3.35.10, the budibase:auth cookie containing the JWT session token is set with httpOnly: false at packages/backend-core/src/utils/utils.ts:218. JavaScript can read this cookie via document.cookie. This means every XSS becomes a full account takeover — the attacker steals the JWT and has persistent access to the victim's account. The cookie also lacks secure: true (sent over plaintext HTTP) and sameSite attribute. This issue has been patched in version 3.35.10.
Patch / fix
- npm @budibase/backend-core 3.35.10
- budibase budibase 3.35.10
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 6 mo ago
Exploit prediction
0.28% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/Budibase/budibase/security/advisories/GHSA-4f9j-vr4p-642r referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N |
| GitHub | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | @budibase/backend-core | <3.35.10 |
3.35.10 |
Affected products
- Budibase budibase
Classification
- Weakness
-
- CWE-1004 Sensitive Cookie Without 'HttpOnly' Flag
References
-
github.com
/Budibase/budibase/releases/tag/3.35.10
web, patch, release-notes
-
github.com
/Budibase/budibase/security/advisories/GHSA-4f9j-vr4p-642r
exploit, web, mitigation, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-42239
advisory
-
github.com
/Budibase/budibase
package
Sources
- CVE List CVE-2026-42239
- GitHub Advisory GHSA-4f9j-vr4p-642r
- NVD CVE-2026-42239
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.