Vulnerability Monitor

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CVE-2020-11945

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).

Security Impact Summary

This vulnerability carries a CRITICAL severity rating with a CVSS v3.1 score of 9.8, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts confidentiality (data exposure), integrity (unauthorized modifications), and availability (service disruption) for affected systems. Impacting 5 products from squid-cache, from debian, from opensuse and 2 others, organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2020, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.

Published

2020-04-23T15:15:14.233

Last Modified

2026-06-17T02:51:06.457

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 9.8 (CRITICAL)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:P/I:P/A:P

Access Vector: NETWORK
Access Complexity: LOW
Authentication: NONE
Confidentiality Impact: PARTIAL
Integrity Impact: PARTIAL
Availability Impact: PARTIAL

Exploitability Score

10.0

Impact Score

6.4

Weaknesses

Type: Primary
CWE-190

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	squid-cache	squid	≤ 3.5.28	Yes
Application	squid-cache	squid	< 4.11	Yes
Application	squid-cache	squid	< 5.0.2	Yes
Operating System	debian	debian_linux	9.0	Yes
Operating System	debian	debian_linux	10.0	Yes
Operating System	opensuse	leap	15.1	Yes
Operating System	fedoraproject	fedora	30	Yes
Operating System	fedoraproject	fedora	31	Yes
Operating System	fedoraproject	fedora	32	Yes
Operating System	canonical	ubuntu_linux	16.04	Yes
Operating System	canonical	ubuntu_linux	18.04	Yes
Operating System	canonical	ubuntu_linux	19.10	Yes
Operating System	canonical	ubuntu_linux	20.04	Yes

References

http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00018.html Mailing List, Third Party Advisory ([email protected])
http://master.squid-cache.org/Versions/v4/changesets/squid-4-eeebf0f37a72a2de08348e85ae34b02c34e9a811.patch Vendor Advisory ([email protected])
http://www.openwall.com/lists/oss-security/2020/04/23/2 Mailing List, Third Party Advisory ([email protected])
http://www.squid-cache.org/Versions/v4/changesets/squid-4-eeebf0f37a72a2de08348e85ae34b02c34e9a811.patch Patch, Vendor Advisory ([email protected])
https://bugzilla.suse.com/show_bug.cgi?id=1170313 Issue Tracking, Third Party Advisory ([email protected])
https://github.com/squid-cache/squid/commit/eeebf0f37a72a2de08348e85ae34b02c34e9a811 Patch, Third Party Advisory ([email protected])
https://github.com/squid-cache/squid/pull/585 Patch, Third Party Advisory ([email protected])
https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html Mailing List, Third Party Advisory ([email protected])
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4FWQRYZJPHAZBLXJ56FPCHJN5X2FP3VA/ ([email protected])
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/H4MWXEZAJSOGRJSS2JCJK4WBSND4IV46/ ([email protected])
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RV2VZWFJNO3B56IVN56HHKJASG5DYUIX/ ([email protected])
https://security.gentoo.org/glsa/202005-05 Third Party Advisory ([email protected])
https://security.netapp.com/advisory/ntap-20210304-0004/ Third Party Advisory ([email protected])
https://usn.ubuntu.com/4356-1/ Third Party Advisory ([email protected])
https://www.debian.org/security/2020/dsa-4682 Third Party Advisory ([email protected])
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00018.html Mailing List, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
http://master.squid-cache.org/Versions/v4/changesets/squid-4-eeebf0f37a72a2de08348e85ae34b02c34e9a811.patch Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
http://www.openwall.com/lists/oss-security/2020/04/23/2 Mailing List, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
http://www.squid-cache.org/Versions/v4/changesets/squid-4-eeebf0f37a72a2de08348e85ae34b02c34e9a811.patch Patch, Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://bugzilla.suse.com/show_bug.cgi?id=1170313 Issue Tracking, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/squid-cache/squid/commit/eeebf0f37a72a2de08348e85ae34b02c34e9a811 Patch, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/squid-cache/squid/pull/585 Patch, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html Mailing List, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4FWQRYZJPHAZBLXJ56FPCHJN5X2FP3VA/ (af854a3a-2127-422b-91ae-364da2661108)
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/H4MWXEZAJSOGRJSS2JCJK4WBSND4IV46/ (af854a3a-2127-422b-91ae-364da2661108)
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RV2VZWFJNO3B56IVN56HHKJASG5DYUIX/ (af854a3a-2127-422b-91ae-364da2661108)
https://security.gentoo.org/glsa/202005-05 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://security.netapp.com/advisory/ntap-20210304-0004/ Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://usn.ubuntu.com/4356-1/ Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.debian.org/security/2020/dsa-4682 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For squid-cache's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.