Squid-cache vulnerabilities
We track 18 vulnerabilities in Squid-cache products. 18 are rated high or critical, and none are known to be exploited. The most recent was published on October 13, 2026.
Latest Squid-cache vulnerabilities
- 7.7 High severity
squid: Inconsistent Interpretation of HTTP Requests
Squid is a caching proxy for the Web. From 3.3.0.1 to before 7.6, due to an improper enforcement of behavioral workflow bug, Squid is vulnerable to a Request Smuggling attack against HTTP/1.1 Transfer-Encoding. HTTP header parsing (`src/HttpHeader.cc`) accepte
- 7.5 High severity
squid: Use After Free
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 agai
- 7.5 High severity
squid: Improper Resource Locking
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
- 7.5 High severity
squid: Generation of Error Message Containing Sensitive Information
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 cr
- 9.8 Critical severity
squid: Out-of-bounds Write
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
- 7.5 High severity
Squid is an open source caching proxy for the Web supporting HTTP, HTTPS, FTP, and more.
Squid is an open source caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to Input Validation, Premature Release of Resource During Expected Lifetime, and Missing Release of Resource after Effective Lifetime bugs, Squid is vulnerable to Deni
- 7.5 High severity
squid: Uncontrolled Recursion
Squid is a web proxy cache. Starting in version 3.5.27 and prior to version 6.8, Squid may be vulnerable to a Denial of Service attack against HTTP Chunked decoder due to an uncontrolled recursion bug. This problem allows a remote attacker to cause Denial of S
- 7.5 High severity
squid: Collapse of Data into Unsafe Value
Squid is an open source caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a Collapse of Data into Unsafe Value bug ,Squid may be vulnerable to a Denial of Service attack against HTTP header parsing. This problem allows a remote client or
- 7.5 High severity
squid: Uncontrolled Recursion
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 p
- 7.5 High severity
squid: Use After Free
Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Affected versions of squid are subject to a a Use-After-Free bug which can lead to a Denial of Service attack via collapsed forwarding. All versions of Squid from 3.5 up to and includi
- 7.5 High severity
squid: Reachable Assertion
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.
- 7.5 High severity
squid: Out-of-bounds Read
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 upgra
- 7.5 High severity
squid: NULL Pointer Dereference
Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a NULL pointer dereference bug Squid is vulnerable to a Denial of Service attack against Squid's Gopher gateway. The gopher protocol is always available and enabled in Squid pri
- 7.5 High severity
Red Hat Enterprise Linux 8: Improper Handling of Exceptional Conditions
A flaw was found in Squid. The limits applied for validation of HTTP response headers are applied before caching. However, Squid may grow a cached HTTP response header beyond the configured maximum size, causing a stall or crash of the worker process when a la
- 7.5 High severity
Red Hat Enterprise Linux 9: Incorrect Conversion between Numeric Types
Squid is vulnerable to Denial of Service, where a remote attacker can perform DoS by sending ftp:// URLs in HTTP Request messages or constructing ftp:// URLs from FTP Native input.
- 7.5 High severity
Red Hat Enterprise Linux 6 Extended Lifecycle…: Buffer Copy without Checking Size of Input
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.
- 7.5 High severity
squid: Improper Certificate Validation
Squid is a caching proxy for the Web. Due to an Improper Validation of Specified Index bug, Squid versions 3.3.0.1 through 5.9 and 6.0 prior to 6.4 compiled using `--with-openssl` are vulnerable to a Denial of Service attack against SSL Certificate validation.
- 8.6 High severity
Squid: Integer Overflow or Wraparound
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 credential