CVE-2017-16086
ReDoS via long UserAgent header in ua-parser
ua-parser is a port of Browserscope's user agent parser. ua-parser is vulnerable to a ReDoS (Regular Expression Denial of Service) attack when given a specially crafted UserAgent header.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
ua-parser is a port of Browserscope's user agent parser. ua-parser is vulnerable to a ReDoS (Regular Expression Denial of Service) attack when given a specially crafted UserAgent header.
- Record
CVE-2017-16086- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-400
- Updated
- 2026-11-02
CVE List No score
ua-parser is a port of Browserscope's user agent parser. ua-parser is vulnerable to a ReDoS (Regular Expression Denial of Service) attack when given a specially crafted UserAgent header.
- Record
CVE-2017-16086- Weakness
- CWE-400
- Updated
- 2026-11-02
EUVDEUVD-2018-0303 No score
ua-parser is a port of Browserscope's user agent parser. ua-parser is vulnerable to a ReDoS (Regular Expression Denial of Service) attack when given a specially crafted UserAgent header.
- Record
EUVD-2018-0303- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-pmg9-p9r2-6q87 No score
ReDoS via long UserAgent header in ua-parser
Affected versions of ua-parser are vulnerable to regular expression denial of service when given a specially crafted User-Agent header.
Recommendation
No patch is currently available for this vulnerability.
The best mitigation is currently to avoid using this package, using a different, functionally equivalent package such as useragent.
- Record
GHSA-pmg9-p9r2-6q87- Weakness
- CWE-400
- Updated
- 2026-11-02
OSVGHSA-pmg9-p9r2-6q87 No score
ReDoS via long UserAgent header in ua-parser
Affected versions of ua-parser are vulnerable to regular expression denial of service when given a specially crafted User-Agent header.
Recommendation
No patch is currently available for this vulnerability.
The best mitigation is currently to avoid using this package, using a different, functionally equivalent package such as useragent.
- Record
GHSA-pmg9-p9r2-6q87- Weakness
- CWE-400
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
ua-parsernpm |
through 0.3.5 | None known |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| Metasploit | ua-parser-js npm module ReDoS |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, Metasploit, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2017-16086 is a high vulnerability (CVSS 7.5) in Ua-parser Project Ua-parser, published June 7, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 9.10%, the 95th percentile. No source names a fixed version.