How severe is CVE-2021-43307?

CVE-2021-43307 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-43307 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43307?

CVE-2021-43307 affects Semver-regex Project Semver-regex. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43307?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-43307 published?

CVE-2021-43307 was published on 2022-06-02 and last updated on 2026-06-17.

CVE-2021-43307

CVE-2021-43307 is a medium-severity vulnerability in Semver-regex Project Semver-regex with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1333.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 5.0
EPSS exploit prediction: 1% (70th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1333
Affected product: Semver-regex Project Semver-regex
Published: 2022-06-02
Last modified: 2026-06-17

Description

An exponential ReDoS (Regular Expression Denial of Service) can be triggered in the semver-regex npm package, when an attacker is able to supply arbitrary input to the test() method

Frequently asked questions

What is CVE-2021-43307?: An exponential ReDoS (Regular Expression Denial of Service) can be triggered in the semver-regex npm package, when an attacker is able to supply arbitrary input to the test() method
How severe is CVE-2021-43307?: CVE-2021-43307 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-43307 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43307?: CVE-2021-43307 affects Semver-regex Project Semver-regex. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43307?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-43307 published?: CVE-2021-43307 was published on 2022-06-02 and last updated on 2026-06-17.

References

https://research.jfrog.com/vulnerabilities/semver-regex-redos-xray-211349/

Affected products (1)

cpe:2.3:a:semver-regex_project:semver-regex:*:*:*:*:*:*:*:*

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