CVE-2021-32819
High PUBLISHEDRemote code execution in squirrelly
Not yet in CISA KEV
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
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.
- CVE Published
- May 14, 2021
- Exploitation Reported
- May 14, 2021
- CVSS
- 8.0 High
- EPSS
- —
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| squirrellyjs |
squirrelly
|
9.0.0 to < 9.0.0 |
Affected |
CVE References
- securitylab.github.com/advisories/GHSL-2021-023-squirrelly securitylab.github.com · CVE Record https://securitylab.github.com/advisories/GHSL-2021-023-squirrelly/
- GitHub — squirrellyjs/squirrelly github.com · CVE Record https://github.com/squirrellyjs/squirrelly/pull/254
- GitHub — squirrellyjs/squirrelly github.com · CVE Record https://github.com/squirrellyjs/squirrelly/commit/c12418a026f73df645b...
- GitHub — squirrellyjs/squirrelly github.com · CVE Record https://github.com/squirrellyjs/squirrelly/commit/dca7a1e7ee91d8a6fff...
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Check enrichment artifacts for scanner coverage and available PoCs before rolling remediation validation.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| The Shadowserver First | 2021-05-14 00:00 UTC |
Scanner Artifacts
Nuclei and Metasploit references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-32819.yaml | Apr 25, 2025 |
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
Exploitation Status
Exploited in the wild
Recorded 2021-05-14 00:00:00 UTC · The Shadowserver
Proof of concept available
Recorded 2021-06-12 17:09:48 UTC · GitHub
Weaknesses (CWE)
-
Exposure of Sensitive Information to an Unauthorized Actor
Scanner Integrations
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-32819.yaml | Apr 25, 2025 |
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
github · Created 2021-06-12 17:09:48 UTC · 10 stars
SquirrellyJS 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.
nuclei · Created Unknown
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
00:00 UTC about 1 year ago00:00 UTC · about 1 year ago
Nuclei template available
Scanner coverage available
-
17:09 UTC about 5 years ago17:09 UTC · about 5 years ago
Public PoC available
Public proof-of-concept code published
-
00:00 UTC about 5 years ago00:00 UTC · about 5 years ago
Added to KEVIntel KEV Feed
High-confidence, third-party attested exploitation
-
00:00 UTC about 5 years ago00:00 UTC · about 5 years ago
CVE published
Vulnerability disclosed publicly
-
00:00 UTC about 5 years ago00:00 UTC · about 5 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2021-32819
{
"cve_id": "CVE-2021-32819",
"title": "Remote code execution in squirrelly",
"affected_vendor": "squirrellyjs",
"affected_product": "squirrelly",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "High",
"cvss_score": 8.0,
"epss_score": null,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}