// For flags

CVE-2021-28543

 

Severity Score

7.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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.

Varnish varnish-modules versiones anteriores a 0.17.1, permite a atacantes remotos causar una denegación de servicio (reinicio del demonio) en algunas configuraciones. Esto no afecta a organizaciones que solo instalan el producto Varnish Cache; sin embargo, es común instalar tanto Varnish Cache como varnish-modules. Específicamente, un error de aserción o desreferencia del puntero NULL se puede activar en Varnish Cache por medio de las funciones header.append() y header.copy() de varnish-modules. Para algunos archivos de Varnish Configuration Language (VCL), esto brinda a clientes remotos la oportunidad de causar un reinicio de Varnish Cache. Un reinicio reduce la disponibilidad y el rendimiento general debido a un mayor número de pérdidas de caché y puede causar una mayor carga en los servidores de backend

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
Low
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
Low
Attack Vector
Network
Attack Complexity
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Partial
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-03-16 CVE Reserved
  • 2021-03-16 CVE Published
  • 2023-11-30 EPSS Updated
  • 2024-08-03 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-476: NULL Pointer Dereference
  • CWE-617: Reachable Assertion
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Varnish-cache
Search vendor "Varnish-cache"
 Varnish-modules
Search vendor "Varnish-cache" for product "Varnish-modules"
 < 0.17.1
Search vendor "Varnish-cache" for product "Varnish-modules" and version " < 0.17.1"
-
Affected
Varnish-cache
Search vendor "Varnish-cache"
 Varnish-modules Klarlack
Search vendor "Varnish-cache" for product "Varnish-modules Klarlack"
 < 0.17.1
Search vendor "Varnish-cache" for product "Varnish-modules Klarlack" and version " < 0.17.1"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 34
Search vendor "Fedoraproject" for product "Fedora" and version "34"
-
Affected