How severe is CVE-2026-42604?

CVE-2026-42604 has a CVSS 4.0 base score of 6.9, rated medium severity.

Is CVE-2026-42604 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-42604?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-42604 have an EU (EUVD) identifier?

Yes. CVE-2026-42604 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36543.

When was CVE-2026-42604 published?

CVE-2026-42604 was published on 2026-06-12 and last updated on 2026-06-17.

CVE-2026-42604

CVE-2026-42604 is a medium-severity vulnerability with a CVSS 4.0 base score of 6.9. 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-863.

Key facts

Severity: Medium (CVSS 4.0 base score 6.9)
EPSS exploit prediction: 0% (32nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-36543
Weakness: CWE-863
Published: 2026-06-12
Last modified: 2026-06-17

Description

Actual is a local-first personal finance tool. The `POST /openid/config` endpoint in Actual Budget's sync-server versions <= 26.4.0 exposes the full OpenID Connect configuration—including the OAuth2 `client_secret`—to any caller who knows the bootstrap password. The endpoint also lacks authentication and rate limiting, making the bootstrap password brute-forceable. Version 26.5.0 fixes the issue.

Frequently asked questions

What is CVE-2026-42604?: Actual is a local-first personal finance tool. The `POST /openid/config` endpoint in Actual Budget's sync-server versions <= 26.4.0 exposes the full OpenID Connect configuration—including the OAuth2 `client_secret`—to any caller who knows the bootstrap password. The endpoint also lacks authentication and rate limiting, making the bootstrap password brute-forceable. Version 26.5.0 fixes the issue.
How severe is CVE-2026-42604?: CVE-2026-42604 has a CVSS 4.0 base score of 6.9, rated medium severity.
Is CVE-2026-42604 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-42604?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-42604 have an EU (EUVD) identifier?: Yes. CVE-2026-42604 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36543.
When was CVE-2026-42604 published?: CVE-2026-42604 was published on 2026-06-12 and last updated on 2026-06-17.

References

Other CWE-863 (Incorrect Authorization) vulnerabilities

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CVE-2026-46595 — Critical (CVSS 10.0): Previously, CVE-2024-45337 fixed an authorization bypass for misused ssh server configurations; if any other type of…
CVE-2026-33105 — Critical (CVSS 10.0): Improper authorization in Microsoft Azure Kubernetes Service allows an unauthorized attacker to elevate privileges over…
CVE-2026-32213 — Critical (CVSS 10.0): Improper authorization in Azure AI Foundry allows an unauthorized attacker to elevate privileges over a network.

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