// For flags

CVE-2018-1000027

squid: Incorrect pointer handling in HTTP processing and certificate download can lead to denial of service

Severity Score

7.5
*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

The Squid Software Foundation Squid HTTP Caching Proxy version prior to version 4.0.23 contains a NULL Pointer Dereference vulnerability in HTTP Response X-Forwarded-For header processing that can result in Denial of Service to all clients of the proxy. This attack appear to be exploitable via Remote HTTP server responding with an X-Forwarded-For header to certain types of HTTP request. This vulnerability appears to have been fixed in 4.0.23 and later.

Squid Software Foundation Squid HTTP Caching Proxy, en versiones anteriores a la 4.0.23, contiene una vulnerabilidad de desreferencia de puntero NULL en el procesamiento de cabeceras HTTP Response X-Forwarded-For. Esto puede resultar en una denegación de servicio (DoS) para todos los clientes que empleen el proxy. Este ataque parece ser explotable mediante un servidor HTTP remoto que responda con una cabecera X-Forwarded-For a ciertos tipos de petición HTTP. Parece ser que la vulnerabilidad se ha solucionado en la versión 4.0.23 y siguientes.

Mathias Fischer discovered that Squid incorrectly handled certain long strings in headers. A malicious remote server could possibly cause Squid to crash, resulting in a denial of service. This issue was only addressed in Ubuntu 16.04 LTS. William Lima discovered that Squid incorrectly handled XML parsing when processing Edge Side Includes. A malicious remote server could possibly cause Squid to crash, resulting in a denial of service. This issue was only addressed in Ubuntu 16.04 LTS. Various other issues were also addressed.

*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
High
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
  • 2018-01-29 CVE Reserved
  • 2018-02-05 CVE Published
  • 2024-08-05 CVE Updated
  • 2025-03-26 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-117: Improper Output Neutralization for Logs
  • CWE-476: NULL Pointer Dereference
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"
 < 4.0.23
Search vendor "Squid-cache" for product "Squid" and version " < 4.0.23"
-
Affected
Debian
Search vendor "Debian"
 Debian Linux
Search vendor "Debian" for product "Debian Linux"
 7.0
Search vendor "Debian" for product "Debian Linux" and version "7.0"
-
Affected
Debian
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 Debian Linux
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 8.0
Search vendor "Debian" for product "Debian Linux" and version "8.0"
-
Affected
Debian
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 Debian Linux
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 9.0
Search vendor "Debian" for product "Debian Linux" and version "9.0"
-
Affected
Canonical
Search vendor "Canonical"
 Ubuntu Linux
Search vendor "Canonical" for product "Ubuntu Linux"
 14.04
Search vendor "Canonical" for product "Ubuntu Linux" and version "14.04"
lts
Affected
Canonical
Search vendor "Canonical"
 Ubuntu Linux
Search vendor "Canonical" for product "Ubuntu Linux"
 16.04
Search vendor "Canonical" for product "Ubuntu Linux" and version "16.04"
lts
Affected
Canonical
Search vendor "Canonical"
 Ubuntu Linux
Search vendor "Canonical" for product "Ubuntu Linux"
 17.10
Search vendor "Canonical" for product "Ubuntu Linux" and version "17.10"
-
Affected