CVE-2021-28543

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.

Category

4.0
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.92% Top 30%
Vendor Advisory fedoraproject.org Vendor Advisory varnish-cache.org
Affected: n/a n/a
Published at:
Updated at:

References

Link Tags
https://varnish-cache.org/security/VSV00006.html vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OPFBRQUJNWHCB3GQHSSAPRLQU6Q6PY43/ vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-28543?
CVE-2021-28543 has been scored as a medium severity vulnerability.
How to fix CVE-2021-28543?
To fix CVE-2021-28543, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-28543 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-28543 is being actively exploited. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
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