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Fencer Intel
medium 5.3

CVE-2018-20164 json

uap-core Regular Expression Denial of Service issue

published 2019-02-13 7 y ago modified 2026-06-17 4 mo ago also GHSA-fx7m-j728-mjw3 , EUVD-2019-0379

cvss
5.3
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.3%
EPSS 3.3% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

An issue was discovered in regex.yaml (aka regexes.yaml) in UA-Parser UAP-Core before 0.6.0. A Regular Expression Denial of Service (ReDoS) issue allows remote attackers to overload a server by setting the User-Agent header in an HTTP(S) request to a value containing a long digit string. (The UAP-Core project contains the vulnerability, propagating to all implementations.)

Patch / fix

  • npm uap-core 0.6.0
  • uaparser user_agent_parser-core 0.6.0
  • uap-core Debian 14, Debian 13, Debian 12 20190213-1

debian advisories DEBIAN-CVE-2018-20164

Exploit prediction

3.30% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • x41-dsec.de https://www.x41-dsec.de/lab/advisories/x41-2018-009-uaparser/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
npm uap-core
<0.6.0
0.6.0

Classification

Weakness
  • CWE-185 Incorrect Regular Expression

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.