CVEvulnerability

CVE-2021-28543

7.5 HIGH Published 2021-03-16 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2021-03-16
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
4.0 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:L
CVSS 3.1 ([email protected])
7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0 ([email protected])
5.0 MEDIUM — AV:N/AC:L/Au:N/C:N/I:N/A:P
Weaknesses
CWE-476, CWE-617

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 configurations

• varnish-cache varnish-modules (< 0.17.1) • varnish-cache varnish-modules klarlack (< 0.17.1) • fedoraproject fedora 34

Related

Weakness · CWE (2)

  • CWE-476 NULL Pointer Dereference weakness
  • CWE-617 Reachable Assertion weakness

References