CVE-2021-21353

MEDIUMNVD 6.86.8—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.8 under NVD CVSS v3. EPSS exploit probability: 4.3%, top 10% 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, nvd
Trending — 3 sources updated this weekElevated
6.8
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 4%CVSS: 6.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Pug is an npm package which is a high-performance template engine. In pug before version 3.0.1, if a remote attacker was able to control the pretty option of the pug compiler, e.g. if you spread a user provided object such as the query parameters of a request into the pug template inputs, it was possible for them to achieve remote code execution on the node.js backend. This is fixed in version 3.0.1. This advisory applies to multiple pug packages including "pug", "pug-code-gen". pug-code-gen has a backported fix at version 2.0.3. This advisory is not exploitable if there is no way for un-trusted input to be passed to pug as the pretty option, e.g. if you compile templates in advance before applying user input to them, you do not need to upgrade.

CVSS v3
6.8
EG Score
6.8(medium)
EG Risk
51(Track)
EG Risk 51/100SSVC: Track

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 computed
Severity68% × 45%
Exploitation40% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
90.1%
KEV
Not listed

Published

March 3, 2021

Last Modified

May 27, 2025

References (14)

Affected Packages

(2 across 1 ecosystem)
npm(2)
PackageVulnerable rangeFixed inDependents
pug—3.0.1—
pug-code-gen—3.0.2—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 50× 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.

Showing the most recent 100 of 104 total refreshes for this CVE.

  1. 2026-07-23 14:15 UTCEPSS rescore
  2. 2026-07-23 01:57 UTCEG score recompute
  3. 2026-07-22 22:43 UTCEG score recompute
  4. 2026-07-22 14:05 UTCEPSS rescore
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  10. 2026-07-19 00:59 UTCOSV refresh
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  1. 2026-07-06 16:25 UTCEPSS rescore
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  8. 2026-07-02 16:57 UTCEPSS rescore
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  10. 2026-07-01 07:48 UTCOSV refresh
  11. 2026-06-30 23:20 UTCEPSS rescore
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  40. 2026-06-13 22:58 UTCEPSS rescore
  41. 2026-06-13 12:43 UTCOSV refresh
  42. 2026-06-12 23:10 UTCEPSS rescore
  43. 2026-06-12 23:10 UTCEPSS rescore
  44. 2026-06-11 13:58 UTCEPSS rescore
  45. 2026-06-10 22:16 UTCEPSS rescore
  46. 2026-06-10 22:16 UTCEPSS rescore
  47. 2026-06-10 13:20 UTCEPSS rescore
  48. 2026-06-08 14:15 UTCEPSS rescore
  49. 2026-06-08 14:15 UTCEPSS rescore
  50. 2026-06-07 15:23 UTCEPSS rescore
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  52. 2026-06-06 13:46 UTCEPSS rescore
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  63. 2026-06-01 13:50 UTCEPSS rescore
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  65. 2026-05-31 22:29 UTCEPSS rescore
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  72. 2026-05-27 13:39 UTCEPSS rescore
  73. 2026-05-26 20:15 UTCEG score recompute
  74. 2026-05-26 13:42 UTCEPSS rescore
  75. 2026-05-26 13:42 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCjinsu9758/PUG-RCE-CVE-2021-21353-POC
    First seen Mar 29, 2025
    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-21353?
CVE-2021-21353 is a medium vulnerability published on March 3, 2021. Pug is an npm package which is a high-performance template engine. In pug before version 3.0.1, if a remote attacker was able to control the pretty option of the pug compiler, e.g. if you spread a user provided object such as the query parameters of a request into the pug template inputs, it was…
When was CVE-2021-21353 disclosed?
CVE-2021-21353 was first published in the National Vulnerability Database on March 3, 2021, with the most recent update on May 27, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-21353 actively exploited?
CVE-2021-21353 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 90.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-21353?
CVE-2021-21353 has a CVSS v3 base score of 6.8 (NVD).
How do I remediate CVE-2021-21353?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-21353, 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

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