CVE-2021-40900

HIGHNVD 7.57.5—

7.5

A Regular Expression Denial of Service (ReDOS) vulnerability was discovered in regexfn v1.0.5 when validating crafted invalid emails.

CVSS v3: 7.5
EG Score: 7.5(medium)
EPSS: 56.4%
KEV: Not listed

Published

June 27, 2022

Last Modified

November 21, 2024

References (2)

cve@mitrehttps://github.com/yetingli/SaveResults/blob/main/js/regexfn.js
af854a3a-2127-422b-91ae-364da2661108https://github.com/yetingli/SaveResults/blob/main/js/regexfn.js

Weakness Classification(1)

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

CWE-1333Inefficient Regular Expression Complexity (ReDoS)

Data Freshness Timeline

(refreshed 9× in last 7d / 9× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-25 19:48 UTCEG score recompute
2026-05-25 19:48 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2021-40900?

CVE-2021-40900 is a high vulnerability published on June 27, 2022. A Regular Expression Denial of Service (ReDOS) vulnerability was discovered in regexfn v1.0.5 when validating crafted invalid emails.

When was CVE-2021-40900 disclosed?

CVE-2021-40900 was first published in the National Vulnerability Database on June 27, 2022, 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-2021-40900 actively exploited?

CVE-2021-40900 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 56.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-40900?

CVE-2021-40900 has a CVSS v3 base score of 7.5 (NVD).

How do I remediate CVE-2021-40900?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-40900, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-40900

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CVE-2021-40900

📅 Published

🔄 Last Modified

🔗 References (2)