squid-cache CVEs · Critical

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Overview 11 matches · 0 in Waratek scope · 0 protected · 1 exploited · 0 CISA KEV · 1 public PoC · 1 EPSS ≥ 0.5

11matches 0in Waratek scope0.0% 0protected0.0% 1exploited9.1% 0CISA KEV0.0% 1public PoC9.1% 1EPSS ≥ 0.59.1%

Protected by Waratek 0 0.0% Rule in development 0 0.0% Mitigation candidate 0 0.0% No exploit published 0 0.0% Outside Waratek scope 0 0.0% Not applicable 11 100.0% Withdrawn CVE 0 0.0%

Critical 11 100.0% High 0 0.0% Medium 0 0.0% Low 0 0.0% None 0 0.0% Unknown 0 0.0%

blocked by ARMR today 0 0.0% partly blocked 0 0.0% not blocked 11 100.0% not established 0 0.0% unrecorded 0 0.0%

Exploited 1 9.1% Working exploit published 0 0.0% Proof of concept only 0 0.0% Forecast only 0 0.0% No public exploit 10 90.9%

split by StatusSeverityProtectionExploit maturity peak 4 / year

20193 Not applicable3 Critical3 not blocked3 No public exploit3 20204 Not applicable4 Critical4 not blocked4 No public exploit4 20210 20220 20231 Not applicable1 Critical1 not blocked1 No public exploit1 20240 20252 Not applicable2 Critical2 not blocked2 Exploited1 No public exploit1 20261 Not applicable1 Critical1 not blocked1 No public exploit1

20192020202120222023202420252026

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CVE	Severity	Published▾	Status	Exploitation	Description
CVE-2026-33526	Critical	2026-03-26	Not applicable	No public exploit	Squid is a caching proxy for the Web. Prior to version 7.5, due to heap Use-After-Free, Squid is vulnerable to Denial of Service when handling ICP traffic. This problem allows a remote attacker to perform a reliable and repeatable Denial of Service attack against the Squid service using ICP protocol. This attack is limited to Squid deployments that explicitly enable ICP support (i.e. configure non-zero `icp_port`). This problem _cannot_ be mitigated by denying ICP queries using `icp_access` rules. Version 7.5 contains a patch.
CVE-2025-62168	Critical	2025-10-17	Not applicable	Exploited	Squid is a caching proxy for the Web. In Squid versions prior to 7.2, a failure to redact HTTP authentication credentials in error handling allows information disclosure. The vulnerability allows a script to bypass browser security protections and learn the credentials a trusted client uses to authenticate. This potentially allows a remote client to identify security tokens or credentials used internally by a web application using Squid for backend load balancing. These attacks do not require Squid to be configured with HTTP authentication. The vulnerability is fixed in version 7.2. As a workaround, disable debug information in administrator mailto links generated by Squid by configuring squid.conf with email_err_data off.
CVE-2025-54574	Critical	2025-08-01	Not applicable	No public exploit	Squid is a caching proxy for the Web. In versions 6.3 and below, Squid is vulnerable to a heap buffer overflow and possible remote code execution attack when processing URN due to incorrect buffer management. This has been fixed in version 6.4. To work around this issue, disable URN access permissions.
CVE-2023-46846	Critical	2023-11-03	Not applicable	No public exploit	SQUID is vulnerable to HTTP request smuggling, caused by chunked decoder lenience, allows a remote attacker to perform Request/Response smuggling past firewall and frontend security systems.
CVE-2020-15049	Critical	2020-06-30	Not applicable	No public exploit	An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A Request Smuggling and Poisoning attack can succeed against the HTTP cache. The client sends an HTTP request with a Content-Length header containing "+\ "-" or an uncommon shell whitespace character prefix to the length field-value.
CVE-2020-11945	Critical	2020-04-23	Not applicable	No public exploit	An issue was discovered in Squid before 5.0.2. A remote attacker can replay a sniffed Digest Authentication nonce to gain access to resources that are otherwise forbidden. This occurs because the attacker can overflow the nonce reference counter (a short integer). Remote code execution may occur if the pooled token credentials are freed (instead of replayed as valid credentials).
CVE-2019-12524	Critical	2020-04-15	Not applicable	No public exploit	An issue was discovered in Squid through 4.7. When handling requests from users, Squid checks its rules to see if the request should be denied. Squid by default comes with rules to block access to the Cache Manager, which serves detailed server information meant for the maintainer. This rule is implemented via url_regex. The handler for url_regex rules URL decodes an incoming request. This allows an attacker to encode their URL to bypass the url_regex check, and gain access to the blocked resource.
CVE-2019-12519	Critical	2020-04-15	Not applicable	No public exploit	An issue was discovered in Squid through 4.7. When handling the tag esi:when when ESI is enabled, Squid calls ESIExpression::Evaluate. This function uses a fixed stack buffer to hold the expression while it's being evaluated. When processing the expression, it could either evaluate the top of the stack, or add a new member to the stack. When adding a new member, there is no check to ensure that the stack won't overflow.
CVE-2019-12526	Critical	2019-11-26	Not applicable	No public exploit	An issue was discovered in Squid before 4.9. URN response handling in Squid suffers from a heap-based buffer overflow. When receiving data from a remote server in response to an URN request, Squid fails to ensure that the response can fit within the buffer. This leads to attacker controlled data overflowing in the heap.
CVE-2019-12523	Critical	2019-11-26	Not applicable	No public exploit	An issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is made. This HTTP request doesn't go through the access checks that incoming HTTP requests go through. This causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker can connect to HTTP servers that only listen on localhost.
CVE-2019-12525	Critical	2019-07-11	Not applicable	No public exploit	An issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use Digest authentication, it parses the header Proxy-Authorization. It searches for certain tokens such as domain, uri, and qop. Squid checks if this token's value starts with a quote and ends with one. If so, it performs a memcpy of its length minus 2. Squid never checks whether the value is just a single quote (which would satisfy its requirements), leading to a memcpy of its length minus 1.

CVE

Severity

Published▾

Status

Exploitation

Description

CVE-2026-33526

Critical

2026-03-26

Not applicable

No public exploit

Squid is a caching proxy for the Web. Prior to version 7.5, due to heap Use-After-Free, Squid is vulnerable to Denial of Service when handling ICP traffic. This problem allows a remote attacker to perform a reliable and repeatable Denial of Service attack against the Squid service using ICP protocol. This attack is limited to Squid deployments that explicitly enable ICP support (i.e. configure non-zero `icp_port`). This problem _cannot_ be mitigated by denying ICP queries using `icp_access` rules. Version 7.5 contains a patch.

CVE-2025-62168

Critical

2025-10-17

Not applicable

Exploited

Squid is a caching proxy for the Web. In Squid versions prior to 7.2, a failure to redact HTTP authentication credentials in error handling allows information disclosure. The vulnerability allows a script to bypass browser security protections and learn the credentials a trusted client uses to authenticate. This potentially allows a remote client to identify security tokens or credentials used internally by a web application using Squid for backend load balancing. These attacks do not require Squid to be configured with HTTP authentication. The vulnerability is fixed in version 7.2. As a workaround, disable debug information in administrator mailto links generated by Squid by configuring squid.conf with email_err_data off.

CVE-2025-54574

Critical

2025-08-01

Not applicable

No public exploit

Squid is a caching proxy for the Web. In versions 6.3 and below, Squid is vulnerable to a heap buffer overflow and possible remote code execution attack when processing URN due to incorrect buffer management. This has been fixed in version 6.4. To work around this issue, disable URN access permissions.

CVE-2023-46846

Critical

2023-11-03

Not applicable

No public exploit

SQUID is vulnerable to HTTP request smuggling, caused by chunked decoder lenience, allows a remote attacker to perform Request/Response smuggling past firewall and frontend security systems.

CVE-2020-15049

Critical

2020-06-30

Not applicable

No public exploit

An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A Request Smuggling and Poisoning attack can succeed against the HTTP cache. The client sends an HTTP request with a Content-Length header containing "+\ "-" or an uncommon shell whitespace character prefix to the length field-value.

CVE-2020-11945

Critical

2020-04-23

Not applicable

No public exploit

An issue was discovered in Squid before 5.0.2. A remote attacker can replay a sniffed Digest Authentication nonce to gain access to resources that are otherwise forbidden. This occurs because the attacker can overflow the nonce reference counter (a short integer). Remote code execution may occur if the pooled token credentials are freed (instead of replayed as valid credentials).

CVE-2019-12524

Critical

2020-04-15

Not applicable

No public exploit

An issue was discovered in Squid through 4.7. When handling requests from users, Squid checks its rules to see if the request should be denied. Squid by default comes with rules to block access to the Cache Manager, which serves detailed server information meant for the maintainer. This rule is implemented via url_regex. The handler for url_regex rules URL decodes an incoming request. This allows an attacker to encode their URL to bypass the url_regex check, and gain access to the blocked resource.

CVE-2019-12519

Critical

2020-04-15

Not applicable

No public exploit

An issue was discovered in Squid through 4.7. When handling the tag esi:when when ESI is enabled, Squid calls ESIExpression::Evaluate. This function uses a fixed stack buffer to hold the expression while it's being evaluated. When processing the expression, it could either evaluate the top of the stack, or add a new member to the stack. When adding a new member, there is no check to ensure that the stack won't overflow.

CVE-2019-12526

Critical

2019-11-26

Not applicable

No public exploit

An issue was discovered in Squid before 4.9. URN response handling in Squid suffers from a heap-based buffer overflow. When receiving data from a remote server in response to an URN request, Squid fails to ensure that the response can fit within the buffer. This leads to attacker controlled data overflowing in the heap.

CVE-2019-12523

Critical

2019-11-26

Not applicable

No public exploit

An issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is made. This HTTP request doesn't go through the access checks that incoming HTTP requests go through. This causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker can connect to HTTP servers that only listen on localhost.

CVE-2019-12525

Critical

2019-07-11

Not applicable

No public exploit

An issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use Digest authentication, it parses the header Proxy-Authorization. It searches for certain tokens such as domain, uri, and qop. Squid checks if this token's value starts with a quote and ends with one. If so, it performs a memcpy of its length minus 2. Squid never checks whether the value is just a single quote (which would satisfy its requirements), leading to a memcpy of its length minus 1.