UpHeron
All vulnerabilities

Servers and applications

CVE-2019-12523

An issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is made. This HTTP request doesn't go through the access checks that incoming HTTP requests go through. This causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker can connect to HTTP servers that only listen on localhost.

Severity
Critical 9.1
Published
26 Nov 2019
Last changed
17 Jun 2026
Added to UpHeron
1 Nov 2026
Exploit chance
4.3% in the next 30 daysHigher than 91% of CVEs. EPSS by FIRST, 10 Nov 2026
Sources
NVD

Affected software

SoftwareAffected versions
SquidServers and applications · cpe:a:squid-cache:squid
  • From 3.0 up to 3.5.28
  • From 4.0 up to 4.8

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2019-12523
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2019-12523