Quick answers
- Is CVE-2021-21317 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2021-21317 being exploited in the wild.
- How severe is CVE-2021-21317?
- Low severity, with a CVSS score of 3.1, published 2 February 2021.
- Which products and versions are affected?
- uap-core (npm) SEMVER:introduced=0,fixed=0.11.0.
- Is there a fix for CVE-2021-21317?
- Yes. uap-core (npm): upgrade to 0.11.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2021-21317 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2021-21317?
- Check whether you run uap-core (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
- uap-core (npm): upgrade to 0.11.0 or later
npm install uap-core@0.11.0
Technical details
The vulnerability is a regular expression denial of service (REDoS) attack caused by overlapping capture groups in regex patterns used to parse User-Agent headers. An attacker can send HTTP requests with specially crafted long User-Agent strings to trigger catastrophic backtracking in the regex engine. This is a network-accessible vulnerability requiring no authentication or user interaction. Successful exploitation results in CPU exhaustion and denial of service. The fix is available in uap-core version 0.11.0 and later.
Affected products
- ua-parser uap-core <0.11.0
Identifiers
- CVE-2021-21317
- GHSA-p4pj-mg4r-x6v4
Timeline
- 2021-01-30: disclosed
- 2021-02-02: patched: Version 0.11.0 released