CVE-2021-28543
MEDIUMEPSS 71th pctlDescription
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.
How to fix
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:L
Exploit Intelligence
Elevated risk: more likely to be exploited than 71% of all known CVEs.
References
Related Vulnerabilities
Other CWE-476 (NULL Pointer Dereference) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-21758 | High | 7.5 | 92% | - | Fix |
| CVE-2023-21547 | High | 7.5 | 88% | - | Fix |
| CVE-2014-3470 | Medium | 4.3 | 86% | - | Fix |
| CVE-2021-44224 | High | 8.2 | 82% | - | Fix |
| CVE-2016-0742 | High | 7.5 | 82% | - | Fix |
| CVE-2009-1386 | Medium | 5.0 | 80% | - | Fix |
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.