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Vulnerabilities

Squid-cache .org Squid

Ranked by severity, then by exploit likelihood. Click a CVE ID for its full record.

111CVEs
CVE-2019-18860
Squid before 4.9, when certain web browsers are used, mishandles HTML in the host (aka hostname) parameter to cachemgr.cgi.
Published 2020-03-20 · Modified
6.1EPSS 0.055
CVE-2018-19131
Squid before 4.4 has XSS via a crafted X.509 certificate during HTTP(S) error page generation for certificate errors.
Published 2018-11-09 · Modified
6.1EPSS 0.033
CVE-2016-2390
The FwdState::connectedToPeer method in FwdState.cc in Squid before 3.5.14 and 4.0.x before 4.0.6 does not properly handle SSL handshake errors when built with the --with-openssl option, which allows remote attackers to cause a denial of service (application crash) via a plaintext HTTP message.
Published 2016-04-19 · Modified
5.9EPSS 0.256
CVE-2018-1172
This vulnerability allows remote attackers to deny service on vulnerable installations of The Squid Software Foundation Squid 3.5.27-20180318. Authentication is not required to exploit this vulnerability. The specific flaw exists within ClientRequestContext::sslBumpAccessCheck(). A crafted request can trigger the dereference of a null pointer. An attacker can leverage this vulnerability to create a denial-of-service condition to users of the system. Was ZDI-CAN-6088.
Published 2018-05-16 · Modified
5.9EPSS 0.083
CVE-2019-12529
An issue was discovered in Squid 2.x through 2.7.STABLE9, 3.x through 3.5.28, and 4.x through 4.7. When Squid is configured to use Basic Authentication, the Proxy-Authorization header is parsed via uudecode. uudecode determines how many bytes will be decoded by iterating over the input and checking its table. The length is then used to start decoding the string. There are no checks to ensure that the length it calculates isn't greater than the input buffer. This leads to adjacent memory being decoded as well. An attacker would not be able to retrieve the decoded data unless the Squid maintainer had configured the display of usernames on error pages.
Published 2019-07-11 · Modified
5.9EPSS 0.081
CVE-2018-19132
Squid before 4.4, when SNMP is enabled, allows a denial of service (Memory Leak) via an SNMP packet.
Published 2018-11-09 · Modified
5.9EPSS 0.061
CVE-2019-12521
An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing.
Published 2020-04-15 · Modified
5.9EPSS 0.059
CVE-2026-50012
Squid: Memory corruption in cache_digest reply handling
Published 2026-07-16 · Analyzed
5.5EPSS 0.014
CVE-2021-28116
Squid through 4.14 and 5.x through 5.0.5, in some configurations, allows information disclosure because of an out-of-bounds read in WCCP protocol data. This can be leveraged as part of a chain for remote code execution as nobody.
Published 2021-03-09 · Modified
5.3EPSS 0.129
CVE-2019-18678
An issue was discovered in Squid 3.x and 4.x through 4.8. It allows attackers to smuggle HTTP requests through frontend software to a Squid instance that splits the HTTP Request pipeline differently. The resulting Response messages corrupt caches (between a client and Squid) with attacker-controlled content at arbitrary URLs. Effects are isolated to software between the attacker client and Squid. There are no effects on Squid itself, nor on any upstream servers. The issue is related to a request header containing whitespace between a header name and a colon.
Published 2019-11-26 · Modified
5.3EPSS 0.109
CVE-2013-4123
client_side_request.cc in Squid 3.2.x before 3.2.13 and 3.3.x before 3.3.8 allows remote attackers to cause a denial of service via a crafted port number in a HTTP Host header.
Published 2013-09-16 · Modified
5.01 PoCEPSS 0.805
CVE-2010-3072
The string-comparison functions in String.cci in Squid 3.x before 3.1.8 and 3.2.x before 3.2.0.2 allow remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted request.
Published 2010-09-20 · Modified
5.0EPSS 0.599
CVE-2009-2622
Squid 3.0 through 3.0.STABLE16 and 3.1 through 3.1.0.11 allows remote attackers to cause a denial of service via malformed requests including (1) "missing or mismatched protocol identifier," (2) missing or negative status value," (3) "missing version," or (4) "missing or invalid status number," related to (a) HttpMsg.cc and (b) HttpReply.cc.
Published 2009-07-28 · Modified
5.0EPSS 0.569
CVE-2014-3609
HttpHdrRange.cc in Squid 3.x before 3.3.12 and 3.4.x before 3.4.6 allows remote attackers to cause a denial of service (crash) via a request with crafted "Range headers with unidentifiable byte-range values."
Published 2014-09-11 · Modified
5.0EPSS 0.562
CVE-2011-4096
The idnsGrokReply function in Squid before 3.1.16 does not properly free memory, which allows remote attackers to cause a denial of service (daemon abort) via a DNS reply containing a CNAME record that references another CNAME record that contains an empty A record.
Published 2011-11-17 · Modified
5.0EPSS 0.372
CVE-2009-2855
The strListGetItem function in src/HttpHeaderTools.c in Squid 2.7 allows remote attackers to cause a denial of service via a crafted auth header with certain comma delimiters that trigger an infinite loop of calls to the strcspn function.
Published 2009-08-18 · Modified
5.0EPSS 0.340
CVE-2014-0128
Squid 3.1 before 3.3.12 and 3.4 before 3.4.4, when SSL-Bump is enabled, allows remote attackers to cause a denial of service (assertion failure) via a crafted range request, related to state management.
Published 2014-04-14 · Modified
5.0EPSS 0.329
CVE-2010-2951
dns_internal.cc in Squid 3.1.6, when IPv6 DNS resolution is not enabled, accesses an invalid socket during an IPv4 TCP DNS query, which allows remote attackers to cause a denial of service (assertion failure and daemon exit) via vectors that trigger an IPv4 DNS response with the TC bit set.
Published 2010-10-12 · Modified
5.0EPSS 0.315
CVE-2010-0639
The htcpHandleTstRequest function in htcp.c in Squid 2.x before 2.6.STABLE24 and 2.7 before 2.7.STABLE8, and htcp.cc in 3.0 before 3.0.STABLE24, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via crafted packets to the HTCP port.
Published 2010-02-15 · Modified
5.0EPSS 0.306
CVE-2009-2621
Squid 3.0 through 3.0.STABLE16 and 3.1 through 3.1.0.11 does not properly enforce "buffer limits and related bound checks," which allows remote attackers to cause a denial of service via (1) an incomplete request or (2) a request with a large header size, related to (a) HttpMsg.cc and (b) client_side.cc.
Published 2009-07-28 · Modified
5.0EPSS 0.230
CVE-2013-0189
cachemgr.cgi in Squid 3.1.x and 3.2.x, possibly 3.1.22, 3.2.4, and other versions, allows remote attackers to cause a denial of service (resource consumption) via a crafted request. NOTE: this issue is due to an incorrect fix for CVE-2012-5643, possibly involving an incorrect order of arguments or incorrect comparison.
Published 2013-02-08 · Modified
5.0EPSS 0.230
CVE-2012-5643
Multiple memory leaks in tools/cachemgr.cc in cachemgr.cgi in Squid 2.x and 3.x before 3.1.22, 3.2.x before 3.2.4, and 3.3.x before 3.3.0.2 allow remote attackers to cause a denial of service (memory consumption) via (1) invalid Content-Length headers, (2) long POST requests, or (3) crafted authentication credentials.
Published 2012-12-20 · Modified
5.0EPSS 0.230
CVE-2012-2213
Squid 3.1.9 allows remote attackers to bypass the access configuration for the CONNECT method by providing an arbitrary allowed hostname in the Host HTTP header. NOTE: this issue might not be reproducible, because the researcher is unable to provide a squid.conf file for a vulnerable system, and the observed behavior is consistent with a squid.conf file that was (perhaps inadvertently) designed to allow access based on a "req_header Host" acl regex that matches www.uol.com.br
Published 2012-04-28 · Modified
5.0EPSS 0.122
CVE-2021-28652
An issue was discovered in Squid before 4.15 and 5.x before 5.0.6. Due to incorrect parser validation, it allows a Denial of Service attack against the Cache Manager API. This allows a trusted client to trigger memory leaks that. over time, lead to a Denial of Service via an unspecified short query string. This attack is limited to clients with Cache Manager API access privilege.
Published 2021-05-27 · Modified
4.9EPSS 0.043
CVE-2019-12522
An issue was discovered in Squid through 4.7. When Squid is run as root, it spawns its child processes as a lesser user, by default the user nobody. This is done via the leave_suid call. leave_suid leaves the Saved UID as 0. This makes it trivial for an attacker who has compromised the child process to escalate their privileges back to root.
Published 2020-04-15 · Modified
4.5EPSS 0.003
CVE-2016-4053
Squid 3.x before 3.5.17 and 4.x before 4.0.9 allow remote attackers to obtain sensitive stack layout information via crafted Edge Side Includes (ESI) responses, related to incorrect use of assert and compiler optimization.
Published 2016-04-25 · Modified
4.3EPSS 0.144
CVE-2015-0881
CRLF injection vulnerability in Squid before 3.1.1 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via a crafted header in a response.
Published 2015-02-20 · Modified
4.3EPSS 0.045
CVE-2010-0308
lib/rfc1035.c in Squid 2.x, 3.0 through 3.0.STABLE22, and 3.1 through 3.1.0.15 allows remote attackers to cause a denial of service (assertion failure) via a crafted DNS packet that only contains a header.
Published 2010-02-03 · Modified
4.0EPSS 0.273
CVE-2014-9749
Squid 3.4.4 through 3.4.11 and 3.5.0.1 through 3.5.1, when Digest authentication is used, allow remote authenticated users to retain access by leveraging a stale nonce, aka "Nonce replay vulnerability."
Published 2015-11-06 · Modified
4.0EPSS 0.114
CVE-2025-59362
Squid through 7.1 mishandles ASN.1 encoding of long SNMP OIDs. This occurs in asn_build_objid in lib/snmplib/asn1.c.
Published 2025-09-26 · Analyzed
4.0EPSS 0.004
CVE-2015-3455
Squid 3.2.x before 3.2.14, 3.3.x before 3.3.14, 3.4.x before 3.4.13, and 3.5.x before 3.5.4, when configured with client-first SSL-bump, do not properly validate the domain or hostname fields of X.509 certificates, which allows man-in-the-middle attackers to spoof SSL servers via a valid certificate.
Published 2015-05-18 · Modified
2.6EPSS 0.114
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