Squid
CVE-2020-15810
MEDIUM
Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Lifecycle Timeline
1DescriptionNVD
An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Smuggling attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This allows any client, including browser scripts, to bypass local security and poison the proxy cache and any downstream caches with content from an arbitrary source. When configured for relaxed header parsing (the default), Squid relays headers containing whitespace characters to upstream servers. When this occurs as a prefix to a Content-Length header, the frame length specified will be ignored by Squid (allowing for a conflicting length to be used from another Content-Length header) but relayed upstream.
AnalysisAI
An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Technical ContextAI
This vulnerability is classified as HTTP Request/Response Smuggling (CWE-444), which allows attackers to manipulate HTTP request interpretation between frontend and backend servers. An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Smuggling attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This allows any client, including browser scripts, to bypass local security and poison the proxy cache and any downstream caches with content from an arbitrary source. When configured for relaxed header parsing (the default), Squid relays headers containing whitespace characters to upstream servers. When this occurs as a prefix to a Content-Length header, the frame length specified will be ignored by Squid (allowing for a conflicting length to be used from another Content-Length header) but relayed upstream. Affected products include: Squid-Cache Squid, Canonical Ubuntu Linux, Debian Debian Linux, Fedoraproject Fedora, Opensuse Leap. Version information: before 4.13.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Enforce strict HTTP parsing, normalize requests at proxy layer, use HTTP/2 end-to-end, reject ambiguous headers.
client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host header when absolute-URI i
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 cr
client_side_request.cc in Squid 3.x before 3.5.18 and 4.x before 4.0.10 allows remote servers to cause a denial of servi
Heap-based buffer overflow in the Icmp6::Recv function in icmp/Icmp6.cc in the pinger utility in Squid before 3.5.16 and
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
Buffer overflow in the idnsALookup function in dns_internal.cc in Squid 3.2 through 3.2.11 and 3.3 through 3.3.6 allows
mime_header.cc in Squid before 3.5.18 allows remote attackers to bypass intended same-origin restrictions and possibly c
The pinger in Squid 3.x before 3.4.8 allows remote attackers to obtain sensitive information or cause a denial of servic
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 (
Squid 3.x before 3.5.15 and 4.x before 4.0.7 does not properly append data to String objects, which allows remote server
Squid 3.x before 3.5.16 and 4.x before 4.0.8 improperly perform bounds checking, which allows remote attackers to cause
The pinger in Squid 3.x before 3.4.8 allows remote attackers to obtain sensitive information or cause a denial of servic
Same weakness CWE-444 – HTTP Request/Response Smuggling
View allSame technique Request Smuggling
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External POC / Exploit Code
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