Is CVE-2021-33502 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2021-33502 being exploited in the wild.

How severe is CVE-2021-33502?

Low severity, with a CVSS score of 3.1, published 8 June 2021.

Which products and versions are affected?

normalize-url (npm) SEMVER:introduced=4.3.0,fixed=4.5.1.

Is there a fix for CVE-2021-33502?

Yes. normalize-url (npm): upgrade to 4.5.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2021-33502 attacked?

It is attacked over the network.

Am I affected by CVE-2021-33502?

Check whether you run normalize-url (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2021-33502: normalize-url ReDoS vulnerability in data URL handling

CVE-2021-33502 · Severity: low · CVSS 3.1 · Published 2021-06-08

normalize-url is a popular Node.js library used to standardize and clean up URL strings. A regular expression flaw in the library allows attackers to send specially crafted data: URLs that cause exponential processing delays, effectively freezing or crashing any application that uses the library to process untrusted URLs. This can lead to denial of service attacks against web services.

Vendors: npm.

Quick answers

Is CVE-2021-33502 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2021-33502 being exploited in the wild.
How severe is CVE-2021-33502?: Low severity, with a CVSS score of 3.1, published 8 June 2021.
Which products and versions are affected?: normalize-url (npm) SEMVER:introduced=4.3.0,fixed=4.5.1.
Is there a fix for CVE-2021-33502?: Yes. normalize-url (npm): upgrade to 4.5.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2021-33502 attacked?: It is attacked over the network.
Am I affected by CVE-2021-33502?: Check whether you run normalize-url (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

normalize-url (npm): upgrade to 4.5.1 or later
```
npm install normalize-url@4.5.1
```

Technical details

The vulnerability is a Regular Expression Denial of Service (ReDoS) vulnerability in the normalize-url library, specifically in the handling of data: URLs. The vulnerable regex pattern exhibits catastrophic backtracking when processing malformed or long data: URLs, allowing an attacker to cause exponential CPU consumption. The attack vector is network-accessible if the application processes user-supplied URLs. No authentication is required. An attacker can trigger the vulnerability by sending a specially crafted data: URL, causing the application to hang or become unresponsive. The fix was released in versions 4.5.1, 5.3.1, and 6.0.1, which optimize the regex pattern to prevent backtracking.

Affected products

sindresorhus normalize-url 4.3.0 to 4.5.0, 5.0.0 to 5.3.0, 6.0.0

Identifiers

CVE-2021-33502
GHSA-px4h-xg32-q955

Timeline

2021-05-24: disclosed: NVD publication date
2021-05-28: patched: GitHub advisory reviewed; patches released in versions 4.5.1, 5.3.1, and 6.0.1

References

https://github.com/sindresorhus/normalize-url/commit/b1fdb5120b6d27a88400d8800e67ff5a22bd2103

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