CVE-2017-12425: Integer Overflow
An issue was discovered in Varnish HTTP Cache 4.0.1 through 4.0.4, 4.1.0 through 4.1.7, 5.0.0, and 5.1.0 through 5.1.2. A wrong if statement in the varnishd source code means that particular invalid requests from the client can trigger an assert, related to an Integer Overflow. This causes the varnishd worker process to abort and restart, losing the cached contents in the process. An attacker can therefore crash the varnishd worker process on demand and effectively keep it from serving content - a Denial-of-Service attack. The specific source-code filename containing the incorrect statement varies across releases.
Other sources
Missing check for integer overflow was found in the code handling chunk sizes in HTTP requests. The vulnerability opens up for denial of service (DOS) attacks by a specially crafted HTTP request, which will cause the Varnish daemon to assert and restart, clearing the cache in the process. There is no risk for information leakage or remote execution. The vulnerability is present in all releases of Varnish Cache since version 4.0.1.
— Red Hat
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2017-12425?
CVE-2017-12425 is classified as a medium severity vulnerability due to its potential to cause application crashes.
How do I fix CVE-2017-12425?
To fix CVE-2017-12425, upgrade Varnish HTTP Cache to version 4.0.5, 4.1.8, or 5.1.3 or later.
Which versions of Varnish HTTP Cache are affected by CVE-2017-12425?
CVE-2017-12425 affects Varnish HTTP Cache versions 4.0.1 through 4.0.4, 4.1.0 through 4.1.7, and versions 5.0.0 and 5.1.0 through 5.1.2.
What kind of issue does CVE-2017-12425 represent?
CVE-2017-12425 represents a coding error that can cause an integer overflow and subsequent application assertion failures.
What is the impact of CVE-2017-12425 on users?
Users of affected Varnish versions may experience potential system instability and unexpected crashes when processing invalid client requests.