Vulnerability Details : CVE-2021-21317
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.
Vulnerability category: Denial of service
Products affected by CVE-2021-21317
- cpe:2.3:a:uap-core_project:uap-core:*:*:*:*:*:node.js:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-21317
0.33%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 70 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-21317
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
5.0
|
MEDIUM | AV:N/AC:L/Au:N/C:N/I:N/A:P |
10.0
|
2.9
|
NIST | |
|
5.3
|
MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
3.9
|
1.4
|
NIST | |
|
5.3
|
MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
3.9
|
1.4
|
GitHub, Inc. |
CWE ids for CVE-2021-21317
-
The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.Assigned by: security-advisories@github.com (Secondary)
-
The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.Assigned by: nvd@nist.gov (Primary)
References for CVE-2021-21317
-
https://www.npmjs.com/package/uap-core
uap-core - npmProduct;Third Party Advisory
-
https://github.com/ua-parser/uap-core/commit/dc9925d458214cfe87b93e35346980612f6ae96c
Merge pull request from GHSA-p4pj-mg4r-x6v4 · ua-parser/uap-core@dc9925d · GitHubPatch
-
https://github.com/ua-parser/uap-core/security/advisories/GHSA-p4pj-mg4r-x6v4
Denial of Service in uap-core <=0.10.0 when processing crafted User-Agent strings · Advisory · ua-parser/uap-core · GitHubThird Party Advisory
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