Squid
Squid 3.3
Squid 3.3
The Squid 3.3 reached end of service life on May 1, 2015 — Squid no longer ships security patches or fixes for it. Our third-party support keeps it safe to run: 24/7 engineers manage issues, remediate vulnerabilities, and help you maintain compliance.
End of Service LifeEOSL Date: May 1, 2015
Issue Management
24/7 engineers own your Squid 3.3 incidents end to end.
Vulnerability Remediation
Mitigation and patch-around guidance when the vendor no longer ships fixes.
Compliance Maintenance
Controls evidence and documentation that keep auditors satisfied.
Specifications
- product
- squid
- release
- 3.3
- product Label
- Squid
- release Label
- 3.3
- codename
- lts
- latest Version
- 3.3.14
- release Date
- 2013-02-09
- maintained
- source Url
- https://endoflife.date/squid
Lifecycle Dates
- End of Service Life
- May 1, 2015
- Last OEM Support
- May 1, 2015
OEM vs. 3rd Party Support
See how third-party support compares to the vendor contract for Squid 3.3 — monitoring, break/fix, vulnerability work, operations and compliance, before and after EOSL.
| Feature | OEM Support | 3rd Party Support |
|---|---|---|
| Post-EOSL Support | ||
| Break/Fix Support | Until EOSL | |
| 24/7 Monitoring | ||
| Vulnerability Scanning & Remediation | ||
| Managed Operations | ||
| Procedure & Configuration Review | ||
| Compliance & Audit Documentation | Limited | |
| Discounted Migration to Other Platforms |
Why Choose 3rd Party Support for Squid 3.3?
Vulnerability Remediation
Scanning, mitigation and patch-around guidance for Squid 3.3 when the vendor no longer ships fixes.
Compliance Maintenance
Procedure review, controls evidence and the documentation auditors ask for — maintained continuously, not scrambled at audit time.
24/7 Expert Support
Engineers who know this release monitor, manage and fix issues around the clock — break/fix to managed operations.
Squid 3.3 Support: Frequently Asked Questions
Is the Squid 3.3 still supported?
Squid ended support for the Squid 3.3 on May 1, 2015 — no more patches or fixes from the vendor. Third-party support keeps it covered: our engineers manage issues, remediate vulnerabilities, and help you maintain compliance for as long as you run it.
When is the Squid 3.3 end of service life (EOSL) date?
Squid lists the end of service life for the Squid 3.3 as May 1, 2015.
Can I keep using the Squid 3.3 after its EOSL date?
Yes. EOSL means Squid stops issuing patches and support — the software itself keeps running. Third-party support covers it from there: issue management, security vulnerability remediation, and the compliance documentation auditors ask for, for as long as you choose to run it.
How much does third-party support for the Squid 3.3 cost?
Typically 40-70% below the OEM maintenance renewal price. Exact pricing depends on quantity, service level and location — request a quote and we respond within 24 hours.
Known Vulnerabilities Affecting Squid 3.3
82 published CVEs affect the Squid 3.3, including 47 rated critical or high severity. Squid no longer ships security patches for this release — our engineers provide mitigation guidance, workarounds and hardening support.
| CVE | Severity | CVSS | Published | Summary |
|---|---|---|---|---|
| CVE-2025-62168 | CRITICAL | 10.0 | Oct 17, 2025 | 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 Sq |
| CVE-2020-15049 | CRITICAL | 9.9 | Jun 30, 2020 | 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 | 9.8 | Apr 23, 2020 | 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-2019-12519 | CRITICAL | 9.8 | Apr 15, 2020 | 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-2019-12524 | CRITICAL | 9.8 | Apr 15, 2020 | 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 resour |
| CVE-2019-12526 | CRITICAL | 9.8 | Nov 26, 2019 | 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-2025-54574 | CRITICAL | 9.3 | Aug 1, 2025 | 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 | 9.3 | Nov 3, 2023 | 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-2026-33526 | CRITICAL | 9.2 | Mar 26, 2026 | 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` rule |
| CVE-2019-12523 | CRITICAL | 9.1 | Nov 26, 2019 | 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-2016-4051 | HIGH | 8.8 | Apr 25, 2016 | Buffer overflow in cachemgr.cgi in Squid 2.x, 3.x before 3.5.17, and 4.x before 4.0.9 might allow remote attackers to cause a denial of service or execute arbitrary code by seeding manager reports with crafted data. |
| CVE-2026-32748 | HIGH | 8.7 | Mar 26, 2026 | Squid is a caching proxy for the Web. Prior to version 7.5, due to premature release of resource during expected lifetime and heap Use-After-Free bugs, 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 _can |
| CVE-2023-50269 | HIGH | 8.6 | Dec 14, 2023 | Squid is a caching proxy for the Web. Due to an Uncontrolled Recursion bug in versions 2.6 through 2.7.STABLE9, versions 3.1 through 5.9, and versions 6.0.1 through 6.5, Squid may be vulnerable to a Denial of Service attack against HTTP Request parsing. This problem allows a remote client to perform Denial of Service attack by sending a large X-Forwarded-For header when the follow_x_forwarded_for feature is configured. This bug is fixed by Squid version 6.6. In addition, patches addressing this |
| CVE-2023-49286 | HIGH | 8.6 | Dec 4, 2023 | Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to an Incorrect Check of Function Return Value bug Squid is vulnerable to a Denial of Service attack against its Helper process management. This bug is fixed by Squid version 6.5. Users are advised to upgrade. There are no known workarounds for this vulnerability. |
| CVE-2023-49285 | HIGH | 8.6 | Dec 4, 2023 | Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a Buffer Overread bug Squid is vulnerable to a Denial of Service attack against Squid HTTP Message processing. This bug is fixed by Squid version 6.5. Users are advised to upgrade. There are no known workarounds for this vulnerability. |
| CVE-2023-46847 | HIGH | 8.6 | Nov 3, 2023 | Squid is vulnerable to a Denial of Service, where a remote attacker can perform buffer overflow attack by writing up to 2 MB of arbitrary data to heap memory when Squid is configured to accept HTTP Digest Authentication. |
| CVE-2022-41318 | HIGH | 8.6 | Dec 25, 2022 | A buffer over-read was discovered in libntlmauth in Squid 2.5 through 5.6. Due to incorrect integer-overflow protection, the SSPI and SMB authentication helpers are vulnerable to reading unintended memory locations. In some configurations, cleartext credentials from these locations are sent to a client. This is fixed in 5.7. |
| CVE-2020-25097 | HIGH | 8.6 | Mar 19, 2021 | An issue was discovered in Squid through 4.13 and 5.x through 5.0.4. Due to improper input validation, it allows a trusted client to perform HTTP Request Smuggling and access services otherwise forbidden by the security controls. This occurs for certain uri_whitespace configuration settings. |
| CVE-2020-24606 | HIGH | 8.6 | Aug 24, 2020 | Squid before 4.13 and 5.x before 5.0.4 allows a trusted peer to perform Denial of Service by consuming all available CPU cycles during handling of a crafted Cache Digest response message. This only occurs when cache_peer is used with the cache digests feature. The problem exists because peerDigestHandleReply() livelocking in peer_digest.cc mishandles EOF. |
| CVE-2016-4554 | HIGH | 8.6 | May 10, 2016 | mime_header.cc in Squid before 3.5.18 allows remote attackers to bypass intended same-origin restrictions and possibly conduct cache-poisoning attacks via a crafted HTTP Host header, aka a "header smuggling" issue. |
Showing the 20 most severe of 82 known CVEs.
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