CVE-2021-28543
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.
| Software | From | Fixed in |
|---|---|---|
| varnish-cache / varnish-modules | - | 0.17.1 |
| varnish-cache / varnish-modules_klarlack | - | 0.17.1 |
| fedoraproject / fedora | 34 | 34.x |
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OPFBRQUJNWHCB3GQHSSAPRLQU6Q6PY43/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OPFBRQUJNWHCB3GQHSSAPRLQU6Q6PY43/
- https://varnish-cache.org/security/VSV00006.html
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