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.
CVE-2026-55778
LOWPre-NVD 2.12.1—
EchelonGraph scoreMEDIUM confidence
This low-severity CVE scores 2.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 67% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, secondary
2.1
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 2.1Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 2.1
- EG Score
- 2.1(medium)
- EPSS
- 33.1%
- KEV
- Not listed
Published
June 19, 2026
Last Modified
July 10, 2026
References (7)
- security-advisories@githubhttps://github.com/parse-community/parse-server/commit/97c6a78d19f976ec756c1295f08a8fccab90799a
- security-advisories@githubhttps://github.com/parse-community/parse-server/commit/be12a60d65b6e140481882037fb896b1f951df50
- security-advisories@githubhttps://github.com/parse-community/parse-server/pull/10505
- security-advisories@githubhttps://github.com/parse-community/parse-server/pull/10506
- security-advisories@githubhttps://github.com/parse-community/parse-server/releases/tag/8.6.81
- security-advisories@githubhttps://github.com/parse-community/parse-server/releases/tag/9.9.1-alpha.11
- security-advisories@githubhttps://github.com/parse-community/parse-server/security/advisories/GHSA-v8x7-r927-cc93
Vendor Advisories for CVE-2026-55778(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
npm(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| parse-server | — | 8.6.81 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× in last 7d / 22× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:25 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-16 17:03 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-13 22:31 UTCEPSS rescore
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-08 21:13 UTCEG score recompute▲ 2.10
- 2026-07-08 21:10 UTCMITRE cvelistV5CVSS v3 → 2.1 · CVSS v4 → 2.1
- 2026-06-19 20:22 UTCEG score recompute
Frequently asked(5)
What is CVE-2026-55778?
CVE-2026-55778 is a low vulnerability published on June 19, 2026. 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,…
When was CVE-2026-55778 disclosed?
CVE-2026-55778 was first published in the National Vulnerability Database on June 19, 2026, with the most recent update on July 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55778 actively exploited?
CVE-2026-55778 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 33.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-55778?
CVE-2026-55778 has a CVSS v3 base score of 2.1 (NVD).
How do I remediate CVE-2026-55778?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55778, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-55778
Is Your Infrastructure Affected by CVE-2026-55778?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.