HOMEVULNERABILITIESCVE-2020-11945
CRITICAL

CVE-2020-11945

CWE-190Published: April 23, 2020· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

An issue was discovered in Squid before 5.0.2. A remote attacker can replay a sniffed Digest Authentication nonce to gain access to resources that are otherwise forbidden. This occurs because the attacker can overflow the nonce reference counter (a short integer). Remote code execution may occur if the pooled token credentials are freed (instead of replayed as valid credentials).

NVD Source

Technical Analysis

CVE-2020-11945 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Canonical1 product(s)
ubuntu linux
Debian1 product(s)
debian linux
Fedora1 product(s)
fedora
openSUSE1 product(s)
leap
squid-cache1 product(s)
squid
Source: NVD CPE · 11 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttp://www.squid-cache.org/Versions/v4/changesets/squid-4-eeebf0f37a72a2de08348e85ae34b02c34e9a811.patch
PATCHhttps://github.com/squid-cache/squid/commit/eeebf0f37a72a2de08348e85ae34b02c34e9a811
PATCHhttps://github.com/squid-cache/squid/pull/585
PATCHhttp://www.squid-cache.org/Versions/v4/changesets/squid-4-eeebf0f37a72a2de08348e85ae34b02c34e9a811.patch
PATCHhttps://github.com/squid-cache/squid/commit/eeebf0f37a72a2de08348e85ae34b02c34e9a811
PATCHhttps://github.com/squid-cache/squid/pull/585
ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-05/msg00018.html
ADVISORYhttp://master.squid-cache.org/Versions/v4/changesets/squid-4-eeebf0f37a72a2de08348e85ae34b02c34e9a811.patch
ADVISORYhttp://www.openwall.com/lists/oss-security/2020/04/23/2
ADVISORYhttps://bugzilla.suse.com/show_bug.cgi?id=1170313
ADVISORYhttps://lists.debian.org/debian-lts-announce/2020/07/msg00009.html
ADVISORYhttps://security.gentoo.org/glsa/202005-05
ADVISORYhttps://security.netapp.com/advisory/ntap-20210304-0004/
ADVISORYhttps://usn.ubuntu.com/4356-1/
ADVISORYhttps://www.debian.org/security/2020/dsa-4682
ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-05/msg00018.html
ADVISORYhttp://master.squid-cache.org/Versions/v4/changesets/squid-4-eeebf0f37a72a2de08348e85ae34b02c34e9a811.patch
ADVISORYhttp://www.openwall.com/lists/oss-security/2020/04/23/2
ADVISORYhttps://bugzilla.suse.com/show_bug.cgi?id=1170313
ADVISORYhttps://lists.debian.org/debian-lts-announce/2020/07/msg00009.html
ADVISORYhttps://security.gentoo.org/glsa/202005-05
ADVISORYhttps://security.netapp.com/advisory/ntap-20210304-0004/
ADVISORYhttps://usn.ubuntu.com/4356-1/
ADVISORYhttps://www.debian.org/security/2020/dsa-4682

All References (30)

→
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00018.htmlMailing List · Third Party Advisory
→
http://master.squid-cache.org/Versions/v4/changesets/squid-4-eeebf0f37a72a2de08348e85ae34b02c34e9a811.patchVendor Advisory
→
http://www.openwall.com/lists/oss-security/2020/04/23/2Mailing List · Third Party Advisory
→
http://www.squid-cache.org/Versions/v4/changesets/squid-4-eeebf0f37a72a2de08348e85ae34b02c34e9a811.patchPatch · Vendor Advisory
→
https://bugzilla.suse.com/show_bug.cgi?id=1170313Issue Tracking · Third Party Advisory
→
https://github.com/squid-cache/squid/commit/eeebf0f37a72a2de08348e85ae34b02c34e9a811Patch · Third Party Advisory
→
https://github.com/squid-cache/squid/pull/585Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2020/07/msg00009.htmlMailing List · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4FWQRYZJPHAZBLXJ56FPCHJN5X2FP3VA/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/H4MWXEZAJSOGRJSS2JCJK4WBSND4IV46/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RV2VZWFJNO3B56IVN56HHKJASG5DYUIX/
→
https://security.gentoo.org/glsa/202005-05Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20210304-0004/Third Party Advisory
→
https://usn.ubuntu.com/4356-1/Third Party Advisory
→
https://www.debian.org/security/2020/dsa-4682Third Party Advisory

Quick Facts

CVE IDCVE-2020-11945
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-190
CISA KEVNo
Affected5 vendor(s)
PublishedApr 23, 2020

Related CVEs (CWE-190)

CVE-2012-5143
10.0
CVE-2015-5097
10.0
CVE-2010-3254
10.0
CVE-2012-5835
10.0
CVE-2013-2555
10.0
CVE-2015-5108
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-11945 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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