CVE-2019-12523 Server-side request forgery in n/a

What is CVE-2019-12523?

CVE-2019-12523 is a critical server-side request forgery vulnerability in Canonical Ubuntu Linux, published on 26 Nov 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Which versions are affected by CVE-2019-12523?

It affects 5 products.

Products include Canonical Ubuntu Linux, Debian Debian Linux, Fedoraproject Fedora, Opensuse Leap, Squid-Cache Squid.

How do I fix CVE-2019-12523?

Upgrade to a fixed version.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2019-12523 being exploited?

There is no known exploitation of CVE-2019-12523 in the wild and no public exploit code.

Other vulnerabilities in Canonical Ubuntu Linux

• CVE-2020-11651 SaltStack Salt Authentication Bypass Exploited Critical 9.8
• CVE-2020-7247 OpenSMTPD Remote Code Execution Exploited Critical 9.8
• CVE-2019-16928 Exim Out-of-bounds Write Exploited Critical 9.8
• CVE-2018-6789 Exim Buffer Overflow Exploited Critical 9.8
• CVE-2015-2590 Oracle Java SE and Java SE Embedded Remote Code Execution Exploited Critical 9.8

All Canonical Ubuntu Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2019-12523, GHSA-99vq-f459-jqrg, UBUNTU-CVE-2019-12523.