CVE-2021-21317

Denial of Service in uap-core

MEDIUM
5.3
CVSS Score
Published: February 16, 2021 at 05:45 PM UTC
Updated: June 17, 2026 at 03:35 AM UTC
2 products affected across 2 vendorsUap CoreCore Project Uap Core

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Severity
MEDIUM5.3
Exploit prediction
EPSS 3%

Description

uap-core in an open-source npm package which contains the core of BrowserScope's original user agent string parser. In uap-core before version 0.11.0, some regexes are vulnerable to regular expression denial of service (REDoS) due to overlapping capture groups. This allows remote attackers to overload a server by setting the User-Agent header in an HTTP(S) request to maliciously crafted long strings. This is fixed in version 0.11.0. Downstream packages such as uap-python, uap-ruby etc which depend upon uap-core follow different version schemes.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.11.0
Affected range stops below 0.11.0, so it looks safe — our inference, not a vendor statement
v < 0.11.0
Affected range stops below 0.11.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

5.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-400CWE-1333

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