CVE-2019-12523
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (4.30%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 4.30% probability · 91th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Affected
- squid-cache/squid · canonical/ubuntu linux · fedoraproject/fedora · opensuse/leap · debian/debian linux
- Source
- cve@mitre.org
EPSS 4.3% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00056.htmlBroken Link
- http://www.squid-cache.org/Advisories/SQUID-2019_8.txtThird Party Advisory
- https://bugzilla.suse.com/show_bug.cgi?id=1156329Issue Tracking, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/07/msg00009.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MTM74TU2BSLT5B3H4F3UDW53672NVLMC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UEMOYTMCCFWK5NOXSXEIH5D2VGWVXR67/
- https://usn.ubuntu.com/4213-1/Third Party Advisory
- https://usn.ubuntu.com/4446-1/Third Party Advisory
- https://www.debian.org/security/2020/dsa-4682Third Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00056.htmlBroken Link
- http://www.squid-cache.org/Advisories/SQUID-2019_8.txtThird Party Advisory
- https://bugzilla.suse.com/show_bug.cgi?id=1156329Issue Tracking, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/07/msg00009.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MTM74TU2BSLT5B3H4F3UDW53672NVLMC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UEMOYTMCCFWK5NOXSXEIH5D2VGWVXR67/
- https://usn.ubuntu.com/4213-1/Third Party Advisory
- https://usn.ubuntu.com/4446-1/Third Party Advisory
- https://www.debian.org/security/2020/dsa-4682Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.