CVE-2021-32819
HighExploitedInsecure template handling in Squirrelly
Published May 17, 2021 · Updated Jul 8, 2026 · Also known as GHSA-q8j6-pwqx-pm96
Key Facts
Patch immediately- CVE-2021-32819 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting Squirrelly.
- It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since May 14, 2021. No public exploit code is known.
- EPSS estimates a 58% probability of exploitation in the next 30 days.
- Fixed versions are available, including Squirrelly 9.0.0.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
8.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
58%
Higher than 99.0% of all scored CVEs
Exploited in the wild
Yes
2 catalog listings
Public exploit code
None known
Get the full CVE-2021-32819 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
Squirrelly is a template engine implemented in JavaScript that works out of the box with ExpressJS. Squirrelly mixes pure template data with engine configuration options through the Express render API. By overwriting internal configuration options remote code execution may be triggered in downstream applications. This issue is fixed in version 9.0.0. For complete details refer to the referenced GHSL-2021-023.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Feb 7, 2024 | n/a | Not reported |
| CIRCL KEV | May 14, 2021 | n/a | Not reported |
Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected Products
3 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| SquirrellySquirrelly | 8.0.8, >= 9.0.0 | 9.0.0 |
Patched Releases
Squirrelly
9.0.0
Timeline
Added to CIRCL KEV
May 14, 2021
Publicly disclosed
May 17, 2021
Added to Industry KEV feed
Feb 7, 2024
Last updated
Jul 8, 2026
Weakness Type
- CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
References
- advisoryGHSA advisory
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2021-32819
- advisoryhttps://securitylab.github.com/advisories/GHSL-2021-023-squirrelly
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
Squirrelly is a template engine implemented in JavaScript that works out of the box with ExpressJS.
Affected: Squirrelly versions 8.0.8, >= 9.0.0. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since May 14, 2021.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Squirrelly 9.0.0.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Is CVE-2021-32819 Running On Your Attack Surface?
Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.
Request A Demo