Is CVE-2026-27804 in the CISA KEV catalog?

No. CVE-2026-27804 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-27804?

CVE-2026-27804 has a CVSS v3 base score of 9.1 (CRITICAL).

What is the EPSS score for CVE-2026-27804?

CVE-2026-27804 has an EPSS score of 0.18% (7th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-27804?

Upgrade parse-server to 9.3.1 or later.

CVE & CISA-KEV Catalog

CVE-2026-27804

CRITICAL

9.1

CVSS v3

NVD

Description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.3 and 9.1.1-alpha.4, an unauthenticated attacker can forge a Google authentication token with `alg: "none"` to log in as any user linked to a Google account, without knowing their credentials. All deployments with Google authentication enabled are affected. The fix in versions 8.6.3 and 9.1.1-alpha.4 hardcodes the expected `RS256` algorithm instead of trusting the JWT header, and replaces the Google adapter's custom key fetcher with `jwks-rsa` which rejects unknown key IDs. As a workaround, dsable Google authentication until upgrading is possible.

CWE-327 CWE-345

How to fix

Remediation Available

parse-serverNVD

Affected:>= 9.0.0, < 9.3.1Fixed in:9.3.1CVE-2026-27804derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Exploit Intelligence

0.18%probability of exploitation in 30 days

7thpercentile

Low risk: more likely to be exploited than 7% of all known CVEs.

References

Patch3

Release Notes2

Related Vulnerabilities

Other CWE-327 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2015-2808	Low	3.7	74%	-	Fix
CVE-2023-34039	Critical	9.8	64%	-	Fix
CVE-2016-6602	Critical	9.8	55%	-	-
CVE-2014-8687	Critical	9.8	44%	-	-
CVE-2020-13777	High	7.4	18%	-	Fix
CVE-2017-17428	Medium	5.9	15%	-	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-04.