GHSA-827p-g5x5-h86c is a medium-severity (CVSS 5.9) CWE-248 vulnerability in parse-server. A fix is available for parse-server — see the affected versions and patch details below.
Parse Server LiveQuery subscription with invalid regular expression crashes server
Exploitation Status
No confirmed exploitation observed yet
- 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 GHSA-827p-g5x5-h86c.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-827p-g5x5-h86c plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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.
parse-servernpmDescription
Impact
A remote attacker can crash the Parse Server by subscribing to a LiveQuery with an invalid regular expression pattern. The server process terminates when the invalid pattern reaches the regex engine during subscription matching, causing denial of service for all connected clients.
Patches
The fix validates regular expression patterns at subscription time, rejecting invalid patterns before they are stored. Additionally, a defense-in-depth try-catch prevents any subscription matching error from crashing the server process.
Workarounds
Disable LiveQuery if it is not needed.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | parse-server | ≥ 9.0.0&&< 9.6.0-alpha.19 | 9.6.0-alpha.19npm install parse-server@9.6.0-alpha.19 |
| 📦npm | parse-server | all versions | 8.6.43npm install parse-server@8.6.43 |
Detection & mitigation playbook
Open-source dependencyDetect
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.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-827p-g5x5-h86c is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-827p-g5x5-h86c can be triaged on real exposure rather than presence alone.
Tailored to GHSA-827p-g5x5-h86c. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-827p-g5x5-h86c in your dependencies?
O3 Security finds GHSA-827p-g5x5-h86c across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.