CVE-2021-33623: The trim-newlines package before 3.0.1 and 4.x before 4.0.1 for Node.js has an issue related to regular expres

Q: How do I fix CVE-2021-33623?

trim-newlines: upgrade to 3.0.1, 4.0.1; e-series performance analyzer: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2021-33623 being exploited?

CVE-2021-33623 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-2021-33623 affect?

CVE-2021-33623 affects trim-newlines, e-series performance analyzer, debian linux. Severity is high (CVSS 7.5). The trim-newlines package before 3.0.1 and 4.x before 4.0.1 for Node.js has an issue related to regular expression denial-of-service (ReDoS) for the .end() method.

Q: How urgent is CVE-2021-33623?

Priority 58/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 7.5REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2021-33623 is a high-severity flaw (CVSS 7.5) affecting trim-newlines, e-series performance analyzer, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The trim-newlines package before 3.0.1 and 4.x before 4.0.1 for Node.js has an issue related to regular expression denial-of-service (ReDoS) for the .end() method.

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

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	2.9% (top 13%)
CISA exploited list	No
Weakness	CWE-400
Published	2021-05-28
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · netapp · trim-newlines project

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

Am I affected?

Timeline

2021-05-28 18:15 UTCPublished CVE record published
2026-06-17 03:54 UTCUpdated Record last modified

trim-newlines project trim-newlines UPGRADE

Affected: < 3.0.1 · >= 4.0.0 and < 4.0.1

Fixed in: 3.0.1, 4.0.1

Safe to downgrade to: a release before 4.0.0

1. Check installed version

npm ls trim-newlines

2. UPGRADE to 3.0.1

npm install trim-newlines@">=3.0.1"

3. If no update is available yet, DOWNGRADE to a release before 4.0.0

npm view trim-newlines versions npm install trim-newlines@"<4.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

netapp e-series performance analyzer MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy e-series-performance-analyzer || rpm -q e-series-performance-analyzer || e-series-performance-analyzer --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

debian debian linux MITIGATE

Affected: 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2021-33623?

trim-newlines: upgrade to 3.0.1, 4.0.1; e-series performance analyzer: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-33623 being exploited?

CVE-2021-33623 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-2021-33623 affect?

CVE-2021-33623 affects trim-newlines, e-series performance analyzer, debian linux. Severity is high (CVSS 7.5). The trim-newlines package before 3.0.1 and 4.x before 4.0.1 for Node.js has an issue related to regular expression denial-of-service (ReDoS) for the .end() method.

How urgent is CVE-2021-33623?

Priority 58/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Node.js vulnerabilities · Debian vulnerabilities

References

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