CVE-2021-0237

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 69% 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
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

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

On Juniper Networks EX4300-MP Series, EX4600 Series, EX4650 Series, QFX5K Series deployed as a Virtual Chassis with a specific Layer 2 circuit configuration, Packet Forwarding Engine manager (FXPC) process may crash and restart upon receipt of specific layer 2 frames. Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS on EX4300-MP Series, EX4600 Series, EX4650 Series, QFX5K Series 15.1 versions prior to 15.1R7-S9; 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R2-S13, 17.4R3-S4, 17.4R3-S5; 18.2 versions prior to 18.2R3-S8; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R2-S7, 18.4R3-S6; 19.1 versions prior to 19.1R3-S4; 19.2 versions prior to 19.2R1-S6, 19.2R3-S1; 19.3 versions prior to 19.3R3-S1; 19.4 versions prior to 19.4R2-S4, 19.4R3-S1; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R2, 20.2R3; 20.3 versions prior to 20.3R1-S2, 20.3R2;

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
34(Track)
EG Risk 34/100SSVC: 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
Severity65% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
31%
KEV
Not listed

Published

April 22, 2021

Last Modified

November 21, 2024

References (2)

Data Freshness Timeline

(refreshed 7× in last 7d / 27× 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 125 total refreshes for this CVE.

  1. 2026-08-19 17:00 UTCEPSS rescore
  2. 2026-08-18 13:44 UTCEPSS rescore
  3. 2026-08-17 13:43 UTCEPSS rescore
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  21. 2026-07-28 15:33 UTCEPSS rescore
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  1. 2026-07-23 01:56 UTCEG score recompute
  2. 2026-07-22 22:42 UTCEG score recompute
  3. 2026-07-22 14:05 UTCEPSS rescore
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  6. 2026-07-20 17:04 UTCEPSS rescore
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  21. 2026-07-12 05:44 UTCEPSS rescore
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  23. 2026-07-11 08:25 UTCEPSS rescore
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  25. 2026-07-09 19:07 UTCEPSS rescore
  26. 2026-07-08 15:12 UTCEPSS rescore
  27. 2026-07-07 13:43 UTCEPSS rescore
  28. 2026-07-06 16:25 UTCEPSS rescore
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  43. 2026-06-27 03:06 UTCEPSS rescore
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  45. 2026-06-25 13:48 UTCEPSS rescore
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  49. 2026-06-23 21:31 UTCEPSS rescore
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  51. 2026-06-22 14:23 UTCEPSS rescore
  52. 2026-06-21 14:54 UTCEPSS rescore
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  68. 2026-06-11 13:58 UTCEPSS rescore
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  70. 2026-06-10 22:16 UTCEPSS rescore
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  72. 2026-06-08 14:15 UTCEPSS rescore
  73. 2026-06-07 15:23 UTCEPSS rescore
  74. 2026-06-07 15:23 UTCEPSS rescore
  75. 2026-06-06 13:46 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-0237?
CVE-2021-0237 is a medium vulnerability published on April 22, 2021. On Juniper Networks EX4300-MP Series, EX4600 Series, EX4650 Series, QFX5K Series deployed as a Virtual Chassis with a specific Layer 2 circuit configuration, Packet Forwarding Engine manager (FXPC) process may crash and restart upon receipt of specific layer 2 frames. Continued receipt and…
When was CVE-2021-0237 disclosed?
CVE-2021-0237 was first published in the National Vulnerability Database on April 22, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-0237 actively exploited?
CVE-2021-0237 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 68.5% of all scored CVEs.
What is the CVSS score of CVE-2021-0237?
CVE-2021-0237 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2021-0237?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-0237, 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.

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