Formbricks before 5.4.4 and 6 before 6.0.1 allows stored XSS. The survey-level Custom Head Scripts feature did not enforce the documented Manage permission boundary. A workspace member holding only readWrite permission could configure Custom Head Scripts on a survey, an operation the documentation restricts to the Manage role. Because the configured scripts execute in the authenticated browser session of any user who opens the affected survey, a lower-privileged member can run arbitrary JavaScript (stored cross-site scripting) in the session of higher-privileged users. Fixed versions require Manage access to modify survey Custom Head Scripts.
CVE-2026-105090
MEDIUMPre-NVD 5.15.1—Trending — 4 sources updated this week
EchelonGraph scoreMEDIUM confidence
This medium-severity CVE scores 5.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (16th percentile of EPSS-scored CVEs). 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
5.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 5.1Exploit: None knownExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 5.1
- EG Score
- 5.1MEDIUMmedium confidence
- EG Risk
- 28EG Risk 28/100CISA SSVC
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity51% × 45%Exploitation0% × 40%Automatability30% × 15%CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.3%
- EPSS %ILE
- 16th
- KEV
- Not listed
CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
October 3, 2026
Last Modified
October 3, 2026
Advisory Details (4)
Auto-updated Oct 3, 2026Patch available. Sources: github_pr, github_release.
generic
CVE-2026-XXXXX — Broken Access Control / Stored XSS w Formbricks (Custom Head Scripts, self-hosted) | SEC4CHECK Blog
https://www.sec4check.pl/blog/posts/cve-formbricks-broken-access-control-stored-xss-custom-head-scripts.htmlgithub_release Patch Available
6.0.1
Patch available: formbricks/formbricks 6.0.1
https://github.com/formbricks/formbricks/releases/tag/6.0.1github_release Patch Available
5.4.4
Patch available: formbricks/formbricks 5.4.4
https://github.com/formbricks/formbricks/releases/tag/5.4.4github_pr
fix(web): require Manage access to change survey custom head scripts
Fix merged in formbricks/formbricks PR #9432 on 2026-09-29 — awaiting tagged release
https://github.com/formbricks/formbricks/pull/9432Vendor Advisories for CVE-2026-105090(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 6× in last 7d / 6× 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.
- 2026-10-04 02:50 UTCEG score recompute
- 2026-10-04 02:49 UTCGHSA enrichment
- 2026-10-03 14:25 UTCEPSS rescore
- 2026-10-03 02:24 UTCEG score recompute
- 2026-10-03 02:05 UTCEG score recompute
- 2026-10-03 02:05 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-105090?
CVE-2026-105090 is a medium vulnerability published on October 3, 2026. Formbricks before 5.4.4 and 6 before 6.0.1 allows stored XSS. The survey-level Custom Head Scripts feature did not enforce the documented Manage permission boundary. A workspace member holding only readWrite permission could configure Custom Head Scripts on a survey, an operation the documentation…
When was CVE-2026-105090 disclosed?
CVE-2026-105090 was first published on October 3, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-105090 actively exploited?
CVE-2026-105090 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (16th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-105090?
CVE-2026-105090 has a CVSS base score of 5.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-105090?
A fix for CVE-2026-105090 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-105090 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-105090
Is Your Infrastructure Affected by CVE-2026-105090?
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