CVE-2020-8450

CVE-2020-8450 affects Squid prior to 4.10, caused by incorrect buffer management in reverse-proxy mode, allowing a remote client to trigger a buffer overflow. Connected advisories confirm a fix was released (e.g., updates to Squid 4.11+/4.10-era patches) across multiple distributions (CloudLinux,...

CVE-2025-62168

Squid (proxy/cache) prior to version 7.2 is affected by information disclosure due to failure to redact HTTP authentication credentials in error handling. The vulnerability can allow a remote, unauthenticated attacker to learn credentials or tokens used by a trusted client or internal web applica...

CVE-2019-12528

Squid is affected by CVE-2019-12528 (pre-4.10). A crafted FTP server can trigger disclosure of sensitive data from heap memory, including data from other sessions or non-Squid processes. Remediation in affected advisories involves upgrading Squid to a later version (at least 4.10+; many advisorie...

CVE-2020-8449

CVE-2020-8449 affects Squid prior to 4.10. The issue arises from improper input validation in HTTP request processing , allowing crafted requests to access resources that should be blocked by security filters. The connected advisories confirm a fix was released across multiple distributions (e.g....

CVE-2021-31806

CVE-2021-31806 is a memory-management bug in Squid’s HTTP Range request processing that enables a Denial of Service against all clients using the proxy. Affected are Squid releases before 4.15 and 5.x before 5.0.6. Public advisories and vendor/procurer notes corroborate impact as DoS (not informa...

CVE-2018-1000027

Summary (CVE-2018-1000027) The Squid HTTP Caching Proxy (Squid Software Foundation) versions prior to 4.0.23 contain a NULL Pointer Dereference vulnerability in HTTP Response X-Forwarded-For header processing that can cause a Denial of Service for all clients of the proxy. Exploitation appears po...

CVE-2019-18860

CVE-2019-18860 affects Squid before 4.9; it mishandles HTML in the host (hostname) parameter to cachemgr.cgi when certain browsers are used. Root cause is improper parsing of that parameter, leading to insecure behavior. The vulnerability is addressed in Squid 4.9+ (upgrade suggested). Exploitati...

CVE-2020-15810

CVE-2020-15810 affects Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Smuggling may succeed against HTTP/HTTPS traffic, leading to cache poisoning and the ability for arbitrary content to be served from upstream caches. When relaxed header parsing is enable...

CVE-2020-15811

CVE-2020-15811 affects Squid before 4.13 and 5.x before 5.0.4, allowing HTTP Request Splitting that can poison caches by mishandling Transfer-Encoding. The issue is confirmed in vendor advisories (ALAS2SQUID4-2023-006; ALAS-2020-1453; ALAS2-2020-1548) which recommend updating Squid to fixed build...

CVE-2020-8517

CVE-2020-8517 affects Squid prior to 4.10. The issue is an out-of-bounds write in the NTLM credentials parser within ext_lm_group_acl caused by incorrect input validation. This can terminate the helper process, which in turn terminates the Squid process and leads to a denial of service for all cl...

CVE-2021-33620

Summary: CVE-2021-33620 affects Squid before 4.15 and 5.x before 5.0.6. It can cause a denial of service across all clients via an HTTP response, triggered by a header that can appear in legitimate traffic. What’s affected: Squid proxy/cache (core components handling HTTP traffic). Root cause (pe...

CVE-2021-31808

CVE-2021-31808 affects Squid before 4.15 and 5.x before 5.0.6. It stems from an input-validation bug in HTTP Range handling that can be exploited to cause a Denial of Service against all clients using the proxy. Affected component: Squid’s HTTP Range request processing. Impact: availability degra...

CVE-2023-5824

Summary: CVE-2023-5824 affects Squid. A flaw in how HTTP response headers are validated before caching allows a header to exceed the configured maximum size, causing a stall or crash of a worker process and resulting in a denial of service. What’s affected: Squid proxy caching server; multiple ad...

CVE-2025-54574

Summary: CVE-2025-54574 affects Squid proxy. In versions 6.3 and older, URN processing causes a heap buffer overflow that can enable remote code execution. Fix released in 6.4; workaround: disable URN access permissions. Multiple advisories (Debian, CloudLinux, Astra Linux, Fedora, etc.) corrobor...

CVE-2026-50012

CVE-2026-50012 describes a heap-based buffer overflow in Squid’s cache_digest reply handling (peerDigestSwapInMask in src/peer_digest.cc). The issue arises from improper input validation where a cache digest’s on-the-wire size can exceed the mask_size declared in the digest, exploitable by a trus...

CVE-2018-19132

CVE-2018-19132 : In Squid, a memory leak occurs when SNMP is enabled, exploitable via SNMP packets to cause denial of service by resource exhaustion. Public advisories confirm a fix in newer Squid releases across multiple distros (e.g., Debian squid3 updates, Mageia 2018-0458, Amazon ALAS/SR pack...

CVE-2023-46728

CVE-2023-46728 affects the Squid proxy where a NULL pointer dereference in Squid’s Gopher gateway can cause a Denial of Service. The issue arises because the obsolete Gopher protocol was always available/enabled in older Squid versions; upstream has removed Gopher support in version 6.0.1, and se...

CVE-2018-19131

CVE-2018-19131 affects Squid prior to 4.4, enabling cross-site scripting via a crafted X.509 certificate during HTTP(S) error page generation for certificate errors. Connected advisories confirm the issue and provide fixes: Amazon Linux 2 ALAS2-2023-2310 lists updated squid packages (e.g., squid-...

CVE-2026-47729

CVE-2026-47729 affects Squid, a web caching proxy. Before 7.6, the FTP gateway (src/clients/FtpGateway.cc) could perform an out-of-bounds read when a directory listing entry date in TypeA/TypeB formats wasn’t followed by a filename, allowing memory disclosure from unrelated transactions. The issu...

CVE-2026-32748

CVE-2026-32748 affects Squid, a web caching proxy. The issue is a heap Use-After-Free in ICP handling, allowing a remote attacker to cause Denial of Service when ICP is enabled (icp_port configured). The attack is remote, requires ICP support, and cannot be mitigated by icp_access rules. A fix is...

CVE-2026-33526

Summary (CVE-2026-33526): Squid before version 7.5 is vulnerable to a Denial of Service via a heap Use-After-Free in ICP traffic handling. The attack requires an ICP-enabled deployment (non-zero icp_port) and remote elicitation, and is described as reliable and repeatable for causing service disr...

CVE-2026-33515

Squid (web caching proxy) is affected by CVE-2026-33515 due to improper input validation in ICP message handling, leading to an out-of-bounds read that may disclose memory contents when responding to invalid ICP requests. The issue is limited to deployments with ICP enabled (icp_port non-zero) an...