CVE-2021-4437

LOWNVD 3.53.5—
EchelonGraph scoreMEDIUM confidence

This low-severity CVE scores 3.5 under NVD CVSS v3. EPSS exploit probability: 0.0%, top 90% 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
Elevated
3.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 3.5Exploit: NoneExposed: 0

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

A vulnerability, which was classified as problematic, has been found in dbartholomae lambda-middleware frameguard up to 1.0.4. Affected by this issue is some unknown functionality of the file packages/json-deserializer/src/JsonDeserializer.ts of the component JSON Mime-Type Handler. The manipulation leads to inefficient regular expression complexity. Upgrading to version 1.1.0 is able to address this issue. The patch is identified as f689404d830cbc1edd6a1018d3334ff5f44dc6a6. It is recommended to upgrade the affected component. VDB-253406 is the identifier assigned to this vulnerability.

CVSS v3
3.5
EG Score
3.5(medium)
EPSS
35.9%
KEV
Not listed

Published

February 12, 2024

Last Modified

November 21, 2024

References (10)

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
@lambda-middleware/json-deserializer—1.1.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 47× 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.

  1. 2026-07-11 08:25 UTCEPSS rescore
  2. 2026-07-09 19:07 UTCEPSS rescore
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  16. 2026-06-30 23:20 UTCEPSS rescore
  17. 2026-06-29 14:04 UTCEPSS rescore
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  22. 2026-06-27 03:07 UTCEPSS rescore
  23. 2026-06-27 03:06 UTCEPSS rescore
  24. 2026-06-26 21:07 UTCOSV refresh
  25. 2026-06-25 13:48 UTCEPSS rescore
Show 57 more
  1. 2026-06-25 13:48 UTCEPSS rescore
  2. 2026-06-24 14:03 UTCEPSS rescore
  3. 2026-06-24 14:03 UTCEPSS rescore
  4. 2026-06-23 21:31 UTCEPSS rescore
  5. 2026-06-23 21:31 UTCEPSS rescore
  6. 2026-06-22 14:24 UTCEPSS rescore
  7. 2026-06-21 14:55 UTCEPSS rescore
  8. 2026-06-21 01:58 UTCEPSS rescore
  9. 2026-06-21 01:58 UTCEPSS rescore
  10. 2026-06-19 19:24 UTCEPSS rescore
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  12. 2026-06-18 17:51 UTCEPSS rescore
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  18. 2026-06-14 23:15 UTCEPSS rescore
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  20. 2026-06-13 22:58 UTCEPSS rescore
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  22. 2026-06-12 23:10 UTCEPSS rescore
  23. 2026-06-11 13:58 UTCEPSS rescore
  24. 2026-06-10 22:16 UTCEPSS rescore
  25. 2026-06-10 13:20 UTCEPSS rescore
  26. 2026-06-09 07:30 UTCOSV refresh
  27. 2026-06-08 14:15 UTCEPSS rescore
  28. 2026-06-08 14:15 UTCEPSS rescore
  29. 2026-06-08 14:15 UTCEPSS rescore
  30. 2026-06-07 15:23 UTCEPSS rescore
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  32. 2026-06-06 13:46 UTCEPSS rescore
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  36. 2026-06-05 06:09 UTCEPSS rescore
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  38. 2026-06-04 13:11 UTCEPSS rescore
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  40. 2026-06-02 20:11 UTCEPSS rescore
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  42. 2026-06-01 13:50 UTCEPSS rescore
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  44. 2026-05-31 22:29 UTCEPSS rescore
  45. 2026-05-31 00:15 UTCEPSS rescore
  46. 2026-05-31 00:15 UTCEPSS rescore
  47. 2026-05-29 13:42 UTCEPSS rescore
  48. 2026-05-28 13:43 UTCEPSS rescore
  49. 2026-05-28 13:43 UTCEPSS rescore
  50. 2026-05-27 13:39 UTCEPSS rescore
  51. 2026-05-27 13:39 UTCEPSS rescore
  52. 2026-05-26 13:43 UTCEPSS rescore
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  54. 2026-05-26 07:17 UTCEPSS rescore
  55. 2026-05-26 07:17 UTCEPSS rescore
  56. 2026-05-24 08:46 UTCEG score recompute
  57. 2026-05-24 01:07 UTCOSV refresh

Frequently asked(5)

What is CVE-2021-4437?
CVE-2021-4437 is a low vulnerability published on February 12, 2024. A vulnerability, which was classified as problematic, has been found in dbartholomae lambda-middleware frameguard up to 1.0.4. Affected by this issue is some unknown functionality of the file packages/json-deserializer/src/JsonDeserializer.ts of the component JSON Mime-Type Handler. The…
When was CVE-2021-4437 disclosed?
CVE-2021-4437 was first published in the National Vulnerability Database on February 12, 2024, 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-2021-4437 actively exploited?
CVE-2021-4437 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 35.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-4437?
CVE-2021-4437 has a CVSS v3 base score of 3.5 (NVD).
How do I remediate CVE-2021-4437?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-4437, 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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