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CRITICAL severity

CVE-2020-28246 — formio

CRITICAL

CVE-2020-28246 is a critical-severity (CVSS 9.8) CWE-74 vulnerability in formio. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

Server-Side Template Injection in formio

Also known asGHSA-52vj-mr2j-f8jh
Published
Updated
Affected
1 pkg
Patched
See advisory
Exploits
None indexed
Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • 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-2020-28246.

EPSS Exploitation Probability

via FIRST.org ↗
2.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs84th percentile — riskier than 84% of all scored CVEsHighest risk
1.68%2.44%3.20%3.95%3.5%2.4%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg 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.

1other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
formionpm
3Kdownloads / week

Description

A Server-Side Template Injection (SSTI) was discovered in Form.io 2.0.0. This leads to Remote Code Execution during deletion of the default Email template URL. NOTE: the email templating service was removed after 2020. Additionally, the vendor disputes this issue indicating this is sandboxed and only executable by admins.

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
📦npmformioall versionsNo fix

Affected Products

1 product · 1 configurations
Application
form.ioform
1 version
2.0.0

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for formio, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Remediation status

    The records we use list no patched version of formio for CVE-2020-28246. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

  3. Mitigate without a patch

    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.

Frequently Asked Questions

A Server-Side Template Injection (SSTI) was discovered in Form.io 2.0.0. This leads to Remote Code Execution during deletion of the default Email template URL. NOTE: the email templating service was removed after 2020. Additionally, the vendor disputes this issue indicating this is sandboxed and only executable by admins.
O3 Security · Impact-Aware SCA

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CVE-2020-28246: formio: Server-Side Template Injection