CVE-2021-3795: semver-regex is vulnerable to Inefficient Regular Expression Complexity

Q: How do I fix CVE-2021-3795?

semver-regex: upgrade to 3.1.3. Exact commands for each OS are on this page.

Q: Is CVE-2021-3795 being exploited?

CVE-2021-3795 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-3795 affect?

CVE-2021-3795 affects semver-regex. Severity is high (CVSS 7.5). semver-regex is vulnerable to Inefficient Regular Expression Complexity

Q: How urgent is CVE-2021-3795?

Priority 55/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2021-3795 is a high-severity flaw (CVSS 7.5) affecting semver-regex. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

semver-regex is vulnerable to Inefficient Regular Expression Complexity

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.5% (top 25%)
CISA exploited list	No
Weakness	CWE-1333
Published	2021-09-15
Last modified	2026-06-17

Publisher (CNA): huntr.dev · Vendor: semver-regex project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-09-15 17:15 UTCPublished CVE record published
2026-06-17 04:05 UTCUpdated Record last modified

semver-regex project semver-regex UPGRADE

Affected: < 3.1.3 · 4.0.0

Fixed in: 3.1.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy semver-regex || rpm -q semver-regex || semver-regex --version

2. UPGRADE to 3.1.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade semver-regex

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade semver-regex

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-3795?

semver-regex: upgrade to 3.1.3. Exact commands for each OS are on this page.

Is CVE-2021-3795 being exploited?

CVE-2021-3795 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-3795 affect?

CVE-2021-3795 affects semver-regex. Severity is high (CVSS 7.5). semver-regex is vulnerable to Inefficient Regular Expression Complexity

How urgent is CVE-2021-3795?

Priority 55/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-43307 MEDIUM 5.9 UPGRADE An exponential ReDoS (Regular Expression Denial of Service) can be triggered in the semver-regex npm package,

References

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