How severe is CVE-2026-31868?

No CVSS score has been assigned to CVE-2026-31868 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-31868?

CVE-2026-31868 affects the following packages: parse-server (npm), parse-server (npm). Ecosystems affected: npm.

How do I fix CVE-2026-31868?

Update parse-server to 9.6.0-alpha.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-31868 is resolved across your whole dependency graph.

How do I detect CVE-2026-31868 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-2026-31868 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-31868 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-31868 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-2026-31868?

CVE-2026-31868 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 17th 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-2026-31868?

CVE-2026-31868 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-31868 published, and has it been updated?

CVE-2026-31868 was published on March 11, 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-2026-31868 — parse-server

CVE-2026-31868 is a Cross-site Scripting (XSS) vulnerability in parse-server. A fix is available for parse-server — see the affected versions and patch details below.

Parse Server has Stored XSS via file upload of HTML-renderable file types

Also known asBIT-parse-2026-31868GHSA-v5hf-f4c3-m5rv

Published

Mar 11, 2026

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Oct 31, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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 CVE-2026-31868.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs17th percentile — riskier than 17% 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

82Kdownloads / week

Description

Impact

An attacker can upload a file with a file extension or content type that is not blocked by the default configuration of the Parse Server fileUpload.fileExtensions option. The file can contain malicious code, for example JavaScript in an SVG or XHTML file. When the file is accessed via its URL, the browser renders the file and executes the malicious code in the context of the Parse Server domain. This is a stored Cross-Site Scripting (XSS) vulnerability that can be exploited to steal session tokens, redirect users, or perform actions on behalf of other users.

Affected file extensions and content types include .svgz, .xht, .xml, .xsl, .xslt, and content types application/xhtml+xml and application/xslt+xml for extensionless uploads. Uploading of .html, .htm, .shtml, .xhtml, and .svg files was already blocked.

Patches

The fix adds the missing file extensions and content types to the default value of the fileUpload.fileExtensions server option.

Workarounds

Configure the fileUpload.fileExtensions server option to block the affected file extensions and content types.

References

GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-v5hf-f4c3-m5rv
Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.6.0-alpha.4
Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.30

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`parse-server`	≥ 9.0.0-alpha.1&&< 9.6.0-alpha.4	9.6.0-alpha.4`npm install parse-server@9.6.0-alpha.4`
📦npm	`parse-server`	all versions	8.6.30`npm install parse-server@8.6.30`

Affected Products

1 product · 5 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.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-31868 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

### Impact An attacker can upload a file with a file extension or content type that is not blocked by the default configuration of the Parse Server `fileUpload.fileExtensions` option. The file can contain malicious code, for example JavaScript in an SVG or XHTML file. When the file is accessed via its URL, the browser renders the file and executes the malicious code in the context of the Parse Server domain. This is a stored Cross-Site Scripting (XSS) vulnerability that can be exploited to steal session tokens, redirect users, or perform actions on behalf of other users. Affected file extens

O3 Security · Impact-Aware SCA

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CVE-2026-31868 — parse-server

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

Real-World Exposure

Description

Impact

Patches

Workarounds

References

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2026-31868 in your dependencies?