How severe is CVE-2026-33527?

No CVSS score has been assigned to CVE-2026-33527 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-33527?

CVE-2026-33527 affects the following packages: parse-server (npm), parse-server (npm). Ecosystems affected: npm.

How do I fix CVE-2026-33527?

Update parse-server to 9.6.0-alpha.48 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33527 is resolved across your whole dependency graph.

How do I detect CVE-2026-33527 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for parse-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-33527 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-33527 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-33527 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-33527?

CVE-2026-33527 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 19th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-33527?

CVE-2026-33527 is classified as CWE-863 (CWE-863). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-33527 published, and has it been updated?

CVE-2026-33527 was published on March 24, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-33527 — parse-server

Fix: parse-community/parse-server@26b628c

CVE-2026-33527 is a CWE-863 vulnerability in parse-server. A fix is available for parse-server — see the affected versions and patch details below.

Parse Server: Session update endpoint allows overwriting server-generated session fields

Also known asBIT-parse-2026-33527GHSA-jc39-686j-wp6q

Published

Mar 24, 2026

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33527.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs19th percentile — riskier than 19% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

62other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

parse-servernpm

65Kdownloads / week

Description

Impact

An authenticated user can overwrite server-generated session fields such as expiresAt and createdWith when updating their own session via the REST API. This allows bypassing the server's configured session lifetime policy, making a session effectively permanent.

Patches

The fix blocks authenticated users from setting expiresAt and createdWith fields when updating a session. Master key and maintenance key operations are not affected.

Workarounds

There is no known workaround other than upgrading.

Resources

GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-jc39-686j-wp6q
Fix Parse Server 9: https://github.com/parse-community/parse-server/pull/10263
Fix Parse Server 8: https://github.com/parse-community/parse-server/pull/10264

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`parse-server`	≥ 9.0.0&&< 9.6.0-alpha.48	9.6.0-alpha.48`npm install parse-server@9.6.0-alpha.48`
📦npm	`parse-server`	all versions	8.6.57`npm install parse-server@8.6.57`

Affected Products

1 product · 49 configurations

Application

parse-serverparseplatform

≥ 9.0.0 && < 9.6.0

1 version

9.6.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for parse-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update parse-server to 9.6.0-alpha.48 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33527 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### Impact An authenticated user can overwrite server-generated session fields such as `expiresAt` and `createdWith` when updating their own session via the REST API. This allows bypassing the server's configured session lifetime policy, making a session effectively permanent. ### Patches The fix blocks authenticated users from setting `expiresAt` and `createdWith` fields when updating a session. Master key and maintenance key operations are not affected. ### Workarounds There is no known workaround other than upgrading. ### Resources - GitHub security advisory: https://github.com/parse

O3 Security · Impact-Aware SCA

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