An update for squid is now available for Red Hat Enterprise Linux 6.Red Hat Product Security has rated this update as having a security impact ofModerate.

A Common Vulnerability Scoring System (CVSS) base score, which gives adetailed severity rating, is available for each vulnerability from the CVElink(s) in the References section.
Squid is a high-performance proxy caching server for web clients, supportingFTP, Gopher, and HTTP data objects.Security Fix(es):* A buffer overflow flaw was found in the way the Squid cachemgr.cgi utilityprocessed remotely relayed Squid input. When the CGI interface utility is used,a remote attacker could possibly use this flaw to execute arbitrary code.(CVE-2016-4051)* Buffer overflow and input validation flaws were found in the way Squidprocessed ESI responses.
If Squid was used as a reverse proxy, or for TLS/HTTPSinterception, a remote attacker able to control ESI components on an HTTP servercould use these flaws to crash Squid, disclose parts of the stack memory, orpossibly execute arbitrary code as the user running Squid. (CVE-2016-4052,CVE-2016-4053, CVE-2016-4054)* An input validation flaw was found in Squid’s mime_get_header_field()function, which is used to search for headers within HTTP requests.

An attackercould send an HTTP request from the client side with specially crafted headerHost header that bypasses same-origin security protections, causing Squidoperating as interception or reverse-proxy to contact the wrong origin server.It could also be used for cache poisoning for client not following RFC 7230.(CVE-2016-4554)* An incorrect reference counting flaw was found in the way Squid processes ESIresponses.
If Squid is configured as reverse-proxy, for TLS/HTTPS interception,an attacker controlling a server accessed by Squid, could crash the squidworker, causing a Denial of Service attack. (CVE-2016-4556)
For details on how to apply this update, which includes the changes described inthis advisory, refer to:https://access.redhat.com/articles/11258After installing this update, the squid service will be restarted automatically.Red Hat Enterprise Linux Server (v. 6)

SRPMS:
squid-3.1.23-16.el6_8.4.src.rpm
    MD5: cc2fbbc9dc4c28cc58c5581aeba84daaSHA-256: 76903d948e9c282b4793b5f960e5b891e78ee0d392752bd831cc5a191c265f65
 
IA-32:
squid-3.1.23-16.el6_8.4.i686.rpm
    MD5: 5907715615213a753bcf38b447b711c5SHA-256: 5b02562e0de3d3fefe6c59919513ffb1f39c8a9e32ba188a8be2066ad3b48e10
squid-debuginfo-3.1.23-16.el6_8.4.i686.rpm
    MD5: 0b49683a57ab9b61944ff5fbfc5943d3SHA-256: 78ff20ea73a3879796688b1b4229584026450a9c3966dbd0df4d755de3250270
 
PPC:
squid-3.1.23-16.el6_8.4.ppc64.rpm
    MD5: 060095592667cc950003b7ab920d2e4cSHA-256: 3884aaca32fbbe31b98cef3e4952a6acd0d334c3dff6a3fa8d3cef2248fcf971
squid-debuginfo-3.1.23-16.el6_8.4.ppc64.rpm
    MD5: 859d5ccd67d20443ef51ed4a5ce1d8deSHA-256: b4ecc524814e607fdbc0ee297f334e847dd8fc8d2a12510c8962e3293b04c4fb
 
s390x:
squid-3.1.23-16.el6_8.4.s390x.rpm
    MD5: ea87ca7da82391caf56954bb78a453fdSHA-256: 0545aed963d3dddc669bc87c80af709dd3964f5b2be8309bad70170d35b8e092
squid-debuginfo-3.1.23-16.el6_8.4.s390x.rpm
    MD5: 6bc62397c794b5e24964aece65a86582SHA-256: 37c53d3282a5e98b93386428454c697226a05fb9cead3dd177667c2dae78844d
 
x86_64:
squid-3.1.23-16.el6_8.4.x86_64.rpm
    MD5: d29cafa641ab538cb8af4d60cef6c2acSHA-256: 5c17f3a82a98118ff86823d8e1f478ad04a61f3e296ee2ce80781d5d6d72745d
squid-debuginfo-3.1.23-16.el6_8.4.x86_64.rpm
    MD5: 7dc32481099d8aa394cf2dc6b3403fb3SHA-256: 1d0913ed4a3afc92c75996c519c0cba0a552c076fd9cdb5d32afce9624bacd51
 
Red Hat Enterprise Linux Workstation (v. 6)

SRPMS:
squid-3.1.23-16.el6_8.4.src.rpm
    MD5: cc2fbbc9dc4c28cc58c5581aeba84daaSHA-256: 76903d948e9c282b4793b5f960e5b891e78ee0d392752bd831cc5a191c265f65
 
IA-32:
squid-3.1.23-16.el6_8.4.i686.rpm
    MD5: 5907715615213a753bcf38b447b711c5SHA-256: 5b02562e0de3d3fefe6c59919513ffb1f39c8a9e32ba188a8be2066ad3b48e10
squid-debuginfo-3.1.23-16.el6_8.4.i686.rpm
    MD5: 0b49683a57ab9b61944ff5fbfc5943d3SHA-256: 78ff20ea73a3879796688b1b4229584026450a9c3966dbd0df4d755de3250270
 
x86_64:
squid-3.1.23-16.el6_8.4.x86_64.rpm
    MD5: d29cafa641ab538cb8af4d60cef6c2acSHA-256: 5c17f3a82a98118ff86823d8e1f478ad04a61f3e296ee2ce80781d5d6d72745d
squid-debuginfo-3.1.23-16.el6_8.4.x86_64.rpm
    MD5: 7dc32481099d8aa394cf2dc6b3403fb3SHA-256: 1d0913ed4a3afc92c75996c519c0cba0a552c076fd9cdb5d32afce9624bacd51
 
(The unlinked packages above are only available from the Red Hat Network)

1329126 – CVE-2016-4051 squid: buffer overflow in cachemgr.cgi1329136 – CVE-2016-4052 CVE-2016-4053 CVE-2016-4054 squid: multiple issues in ESI processing1334241 – CVE-2016-4554 squid: Header Smuggling issue in HTTP Request processing1334786 – CVE-2016-4556 squid: SIGSEGV in ESIContext response handling

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