CVE-2024-30156

varnish: HTTP/2 Broken Window Attack may result in denial of service

Severity Score

7.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Attend

*SSVC

Descriptions

Varnish Cache before 7.3.2 and 7.4.x before 7.4.3 (and before 6.0.13 LTS), and Varnish Enterprise 6 before 6.0.12r6, allows credits exhaustion for an HTTP/2 connection control flow window, aka a Broke Window Attack.

Varnish Cache anterior a 7.3.2 y 7.4.x anterior a 7.4.3 (y anterior a 6.0.13 LTS), y Varnish Enterprise 6 anterior a 6.0.12r6, permite el agotamiento de los créditos para una ventana de flujo de control de conexión HTTP/2, también conocido como ataque de ventana rota.

A flaw was found in the Varnish cache server, with HTTP/2 support enabled, that may allow a Denial of Service type of attack. A malicious actor can cause the server to run out of credits during the HTTP/2 connection control flow. As a consequence, the server will stop to properly process the active HTTP streams, retaining the already allocated resources, leading to resource starvation.

An update for the varnish:6 module is now available for Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support, Red Hat Enterprise Linux 8.4 Telecommunications Update Service, and Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions. Issues addressed include a denial of service vulnerability.

*Credits: N/A

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

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:Attend

Exploitation

None

Automatable

Yes

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-03-24 CVE Reserved
2024-03-24 CVE Published
2024-11-21 CVE Updated
2025-05-02 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-400: Uncontrolled Resource Consumption
CWE-770: Allocation of Resources Without Limits or Throttling

CAPEC

References (4)

URL	Tag	Source
https://varnish-cache.org/docs/7.5/whats-new/changes-7.5.html#security
https://varnish-cache.org/security/VSV00014.html

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://access.redhat.com/security/cve/CVE-2024-30156	2024-07-31
https://bugzilla.redhat.com/show_bug.cgi?id=2271486	2024-07-31

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Oracle Search vendor "Oracle"		Linux Search vendor "Oracle" for product "Linux"				*		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Search vendor "Redhat" for product "Enterprise Linux"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Aus Search vendor "Redhat" for product "Rhel Aus"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel E4s Search vendor "Redhat" for product "Rhel E4s"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Eus Search vendor "Redhat" for product "Rhel Eus"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Software Collections Search vendor "Redhat" for product "Rhel Software Collections"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Tus Search vendor "Redhat" for product "Rhel Tus"				*		-		Affected
Alma Search vendor "Alma"		Linux Search vendor "Alma" for product "Linux"				*		-		Affected
Oracle Search vendor "Oracle"		Linux Search vendor "Oracle" for product "Linux"				*		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Search vendor "Redhat" for product "Enterprise Linux"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Aus Search vendor "Redhat" for product "Rhel Aus"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel E4s Search vendor "Redhat" for product "Rhel E4s"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Eus Search vendor "Redhat" for product "Rhel Eus"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Tus Search vendor "Redhat" for product "Rhel Tus"				*		-		Affected
Rocky Search vendor "Rocky"		Linux Search vendor "Rocky" for product "Linux"				*		-		Affected