Low 2.1Published Jul 8, 2026

CVE-2026-55778Parse Server: Stored XSS via non-standard file extension bypassing file upload extension blocklist

Updated under an hour ago (Oct 26, 2026, 9:40 PM ET)

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It affects parse-community parse-server. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for parse-community parse-server

Exploited in the last 30 days

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.9.1-alpha.11 and 8.6.81, the default fileUpload.fileExtensions blocklist could be bypassed by uploading a file with a non-standard or compound extension and dangerous content type, allowing storage adapters such as S3 and GCS to serve attacker-supplied active content and enable stored cross-site scripting. This issue is fixed in versions 9.9.1-alpha.11 and 8.6.81.

CVSS: 2.1 LOW (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N
Weakness (CWE): CWE-434
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Jul 9, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

parse-community parse-server parse_community:parse_server (from the name)	from 9.0.0-alpha.1, < 9.9.1-alpha.11; before 8.6.81	CNA record

References

References

https://github.com/parse-community/parse-server/security/advisories/GHSA-v8x7-r927-cc93	x-refsource-confirm
https://github.com/parse-community/parse-server/pull/10505	x-refsource-misc
https://github.com/parse-community/parse-server/pull/10506	x-refsource-misc
https://github.com/parse-community/parse-server/commit/97c6a78d19f976ec756c1295f08a8fccab90799a	x-refsource-misc
https://github.com/parse-community/parse-server/commit/be12a60d65b6e140481882037fb896b1f951df50	x-refsource-misc
https://github.com/parse-community/parse-server/releases/tag/8.6.81	x-refsource-misc
https://github.com/parse-community/parse-server/releases/tag/9.9.1-alpha.11	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.