How severe is CVE-2026-42239?

CVE-2026-42239 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-42239 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42239?

CVE-2026-42239 affects Budibase. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-42239?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-42239 have an EU (EUVD) identifier?

Yes. CVE-2026-42239 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28429.

When was CVE-2026-42239 published?

CVE-2026-42239 was published on 2026-05-07 and last updated on 2026-06-17.

CVE-2026-42239

CVE-2026-42239 is a high-severity vulnerability in Budibase with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1004.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 0% (20th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-28429
Weakness: CWE-1004
Affected product: Budibase
Published: 2026-05-07
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2026-42239?: 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.
How severe is CVE-2026-42239?: CVE-2026-42239 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-42239 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42239?: CVE-2026-42239 affects Budibase. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42239?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-42239 have an EU (EUVD) identifier?: Yes. CVE-2026-42239 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28429.
When was CVE-2026-42239 published?: CVE-2026-42239 was published on 2026-05-07 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:budibase:budibase:*:*:*:*:*:*:*:*

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