CVE-2016-3948
HighSummary
Squid versions 3.x before 3.5.16 and 4.x before 4.0.8 improperly perform bounds checking, allowing remote attackers to cause a denial of service via a crafted HTTP response related to Vary headers.
Risk Assessment
Attackers can exploit this vulnerability to disrupt the operation of the proxy server, leading to service unavailability for users.
Recommendation
It is recommended to upgrade Squid to version 3.5.16 or 4.0.8 to mitigate this vulnerability.
Other vulnerabilities in Squid
See all- CVE-2016-4556High
A double free vulnerability in Esi.cc in Squid 3.x before 3.5.18 and 4.x before 4.0.10 allows remote servers to cause a denial of service (crash) via a crafted Edge Side Includes (ESI) response.
- CVE-2016-4554High
The mime_header.cc file in Squid before version 3.5.18 contains a vulnerability that allows remote attackers to bypass intended same-origin restrictions and potentially conduct cache-poisoning attacks via a crafted HTTP Host header, known as a 'header smuggling' issue.
- CVE-2016-4553High
The client_side.cc file in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host header when an absolute URI is provided, allowing remote attackers to conduct cache-poisoning attacks.
- CVE-2016-4054High
A buffer overflow in Squid 3.x before 3.5.17 and 4.x before 4.0.9 allows remote attackers to execute arbitrary code via crafted Edge Side Includes (ESI) responses.
- CVE-2016-4052High
Multiple stack-based buffer overflows in Squid 3.x before 3.5.17 and 4.x before 4.0.9 allow remote HTTP servers to cause a denial of service or execute arbitrary code via crafted Edge Side Includes (ESI) responses.
- CVE-2016-2571High
In Squid 3.x before version 3.5.15 and 4.x before version 4.0.7, http.cc continues to store data after a response-parsing failure. This allows remote HTTP servers to cause a denial of service by sending a malformed response.
- CVE-2016-2569High
Squid versions 3.x before 3.5.15 and 4.x before 4.0.7 do not properly append data to String objects, allowing remote servers to cause a denial of service (assertion failure and daemon exit) via a long string, as demonstrated by a crafted HTTP Vary header.
- CVE-2026-33526High
Squid versions prior to 7.5 contain a heap Use-After-Free vulnerability in ICP traffic handling, allowing a remote attacker to perform a reliable and repeatable Denial of Service attack. The attack requires ICP support enabled (non-zero `icp_port`) and cannot be mitigated by `icp_access` rules.
- CVE-2026-32748High
Squid versions prior to 7.5 have a vulnerability due to premature resource release and heap Use-After-Free bugs, allowing a DoS attack via ICP traffic. This affects only deployments with ICP explicitly enabled (non-zero `icp_port`).
- CVE-2023-46847High
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.
Original NVD description (English source)
Squid 3.x before 3.5.16 and 4.x before 4.0.8 improperly perform bounds checking, which allows remote attackers to cause a denial of service via a crafted HTTP response, related to Vary headers.

