// For flags

CVE-2023-5824

Squid: dos against http and https

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

Squid is vulnerable to Denial of Service attack against HTTP and HTTPS clients due to an Improper Handling of Structural Elements bug.

Squid es vulnerable a ataques de DenegaciĆ³n de Servicio contra clientes HTTP y HTTPS debido a un error en el manejo inadecuado de elementos estructurales.

A flaw was found in Squid. The limits applied for validation of HTTP response headers are applied before caching. However, Squid may grow a cached HTTP response header beyond the configured maximum size, causing a stall or crash of the worker process when a large header is retrieved from the disk cache, resulting in a denial of service.

USN-6728-1 fixed vulnerabilities in Squid. The fix for CVE-2023-5824 caused Squid to crash in certain environments on Ubuntu 20.04 LTS. The problematic fix has been reverted pending further investigation. Joshua Rogers discovered that Squid incorrectly handled collapsed forwarding. A remote attacker could possibly use this issue to cause Squid to crash, resulting in a denial of service. This issue only affected Ubuntu 20.04 LTS and Ubuntu 22.04 LTS. Joshua Rogers discovered that Squid incorrectly handled certain structural elements. A remote attacker could possibly use this issue to cause Squid to crash, resulting in a denial of service. Joshua Rogers discovered that Squid incorrectly handled Cache Manager error responses. A remote trusted client can possibly use this issue to cause Squid to crash, resulting in a denial of service. Joshua Rogers discovered that Squid incorrectly handled the HTTP Chunked decoder. A remote attacker could possibly use this issue to cause Squid to stop responding, resulting in a denial of service. Joshua Rogers discovered that Squid incorrectly handled HTTP header parsing. A remote trusted client can possibly use this issue to cause Squid to crash, resulting in a denial of service.

*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
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2023-10-27 CVE Reserved
  • 2023-11-03 CVE Published
  • 2024-11-23 CVE Updated
  • 2025-03-30 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-755: Improper Handling of Exceptional Conditions
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Squid-cache
Search vendor "Squid-cache"
Squid
Search vendor "Squid-cache" for product "Squid"
< 6.4
Search vendor "Squid-cache" for product "Squid" and version " < 6.4"
-
Affected
Redhat
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Enterprise Linux
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6.0
Search vendor "Redhat" for product "Enterprise Linux" and version "6.0"
-
Affected
Redhat
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Enterprise Linux
Search vendor "Redhat" for product "Enterprise Linux"
7.0
Search vendor "Redhat" for product "Enterprise Linux" and version "7.0"
-
Affected
Redhat
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Enterprise Linux
Search vendor "Redhat" for product "Enterprise Linux"
8.0
Search vendor "Redhat" for product "Enterprise Linux" and version "8.0"
-
Affected
Redhat
Search vendor "Redhat"
Enterprise Linux
Search vendor "Redhat" for product "Enterprise Linux"
9.0
Search vendor "Redhat" for product "Enterprise Linux" and version "9.0"
-
Affected