What is CVE-2026-27804?

CVE-2026-27804 is a critical-severity use of a broken or risky cryptographic algorithm vulnerability in parse-server (npm), affecting versions >= 9.0.0, <= 9.3.1-alpha.3. It is fixed in 9.3.1-alpha.4, 8.6.3. The application uses a cryptographic algorithm known to have weaknesses, such as MD5, SHA-1, or DES.

Which versions of parse-server are affected by CVE-2026-27804?

parse-server (npm) versions >= 9.0.0, <= 9.3.1-alpha.3 is affected.

Is there a fix for CVE-2026-27804?

Yes. CVE-2026-27804 is fixed in 9.3.1-alpha.4, 8.6.3. Upgrade to this version or later.

Is CVE-2026-27804 exploitable, and should I be worried?

Whether CVE-2026-27804 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2026-27804 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

How do I fix CVE-2026-27804?

Upgrade: parse-server to 9.3.1-alpha.4 or later, parse-server to 8.6.3 or later.

CVE-2026-27804 in parse-server | Intelligent Application Security

Q: Which versions of parse-server are affected by CVE-2026-27804?

parse-server (npm) versions >= 9.0.0, <= 9.3.1-alpha.3 is affected.

Q: Is there a fix for CVE-2026-27804?

Yes. CVE-2026-27804 is fixed in 9.3.1-alpha.4, 8.6.3. Upgrade to this version or later.

Q: Is CVE-2026-27804 exploitable, and should I be worried?

Whether CVE-2026-27804 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2026-27804 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2026-27804?

Upgrade: parse-server to 9.3.1-alpha.4 or later, parse-server to 8.6.3 or later.

Summary

Workarounds

Disable Google authentication until you can upgrade.

References

GitHub advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vp4r-prv2
Fixed in Parse Server 9.3.1-alpha.4: https://github.com/parse-community/parse-server/releases/tag/9.3.1-alpha.4
Fixed in Parse Server 8.6.3: https://github.com/parse-community/parse-server/releases/tag/8.6.3

Impact

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 application uses a cryptographic algorithm known to have weaknesses, such as MD5, SHA-1, or DES. Typical impact: compromised confidentiality or integrity of protected data.

Affected versions

parse-server (>= 9.0.0, <= 9.3.1-alpha.3) parse-server (<= 8.6.2)

Security releases

parse-server → 9.3.1-alpha.4 (npm) parse-server → 8.6.3 (npm)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

See it in your environment

Remediation advice

The fix 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.

Frequently Asked Questions

What is CVE-2026-27804? CVE-2026-27804 is a critical-severity use of a broken or risky cryptographic algorithm vulnerability in parse-server (npm), affecting versions >= 9.0.0, <= 9.3.1-alpha.3. It is fixed in 9.3.1-alpha.4, 8.6.3. The application uses a cryptographic algorithm known to have weaknesses, such as MD5, SHA-1, or DES.
Which versions of parse-server are affected by CVE-2026-27804? parse-server (npm) versions >= 9.0.0, <= 9.3.1-alpha.3 is affected.
Is there a fix for CVE-2026-27804? Yes. CVE-2026-27804 is fixed in 9.3.1-alpha.4, 8.6.3. Upgrade to this version or later.
Is CVE-2026-27804 exploitable, and should I be worried? Whether CVE-2026-27804 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2026-27804 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2026-27804?
- Upgrade parse-server to 9.3.1-alpha.4 or later
- Upgrade parse-server to 8.6.3 or later

Other vulnerabilities in parse-server

CVE-IDSeverityPackage summary

GHSA-97PR-9HGG-3P8RLowparse-server: parse-server: LiveQuery discloses object data to a subscriber across an ACL read-access change CVE-2026-55778Lowparse-server: parse-server: Stored XSS via non-standard file extension bypassing file upload extension blocklist CVE-2026-53726Mediumparse-server: parse-server: Relation `$relatedTo` query bypasses `protectedFields` and owning-object ACL CVE-2026-53725Mediumparse-server: parse-server: Endpoints `/login` and `/verifyPassword` disclose MFA secrets and protected fields…CVE-2026-53724Lowparse-server: parse-server: Stored XSS via trailing-dot filename bypassing file upload extension blocklist