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No exploitation reportedFix available

CVE-2020-5243

No exploitation reported by the sources we read.

  • Published2020-02-21
  • Fixed in0.7.3
  • WeaknessCWE-1333 · CWE-20

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

uap-core before 0.7.3 is vulnerable to a denial of service attack when processing crafted User-Agent strings. 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 has been patched in uap-core 0.7.3.

Timeline

dates in UTC
  1. 2020-02-2100:15CVE publishedNVD

Versions per branch

NVD · OSV
Uap-core project uap-core
BranchAffectedFixed in
0.7< 0.7.30.7.3
user_agent_parser
BranchAffectedFixed in
2.6< 2.6.02.6.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • uap-coreUbuntu:26.10all versions · no fixed version listed
  • uap-coreUbuntu:26.04:LTSall versions · no fixed version listed
  • uap-coreUbuntu:25.10all versions · no fixed version listed
  • uap-coreUbuntu:24.04:LTSall versions · no fixed version listed
  • uap-coreUbuntu:22.04:LTSall versions · no fixed version listed
  • uap-coreUbuntu:20.04:LTSall versions · no fixed version listed
  • uap-coreDebian:14all versions · fixed in 1:0.8.0-1
  • uap-coreDebian:13all versions · fixed in 1:0.8.0-1

1 more package range on OSV.dev

Full record on NVD

Fix

  1. Update Uap-core project uap-core to 0.7.3

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CNACVSS 3.15.7known since 2026-10-23
  • NVDCVSS 3.17.5read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • CNAweakness (CWE)CWE-20known since 2026-10-23
  • NVDweakness (CWE)CWE-1333read 2026-10-23
  • FIRST EPSSEPSS score2.3 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryMODERATE2020-02-20

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2020-02-21
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-cmcx-xhr8-3w9p

Frequently asked questions

What is CVE-2020-5243?

uap-core before 0.7.3 is vulnerable to a denial of service attack when processing crafted User-Agent strings. 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 has been patched in uap-core 0.7.3.

Is CVE-2020-5243 actively exploited?

Active exploitation of CVE-2020-5243 has not been confirmed. Its EPSS score was 2.3% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-5243?

CVE-2020-5243 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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