Vulnerability · Published Mar 16, 2021 · Assigned by mitre
CVE-2021-28543
Medium 4.0
In plain English
A medium-severity security flaw in the affected software. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.5% (higher than 74% of all known vulnerabilities).
Official description
Varnish varnish-modules before 0.17.1 allows remote attackers to cause a denial of service (daemon restart) in some configurations. This does not affect organizations that only install the Varnish Cache product; however, it is common to install both Varnish Cache and varnish-modules. Specifically, an assertion failure or NULL pointer dereference can be triggered in Varnish Cache through the varnish-modules header.append() and header.copy() functions. For some Varnish Configuration Language (VCL) files, this gives remote clients an opportunity to cause a Varnish Cache restart. A restart reduces overall availability and performance due to an increased number of cache misses, and may cause higher load on backend servers.
Affected products (as reported)
References
- https://varnish-cache.org/security/VSV00006.html x_refsource_MISC
- FEDORA-2021-2ad352ec70 vendor-advisory, x_refsource_FEDORA