CVE-2019-18676

mediumpriority · track · 33EPSS 0.092 · 95 %ileDEEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

9.18% (95th) EPSS

CVSS 5 · medium

Is it mine?

61 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-27

An issue was discovered in Squid 3.x and 4.x through 4.8. Due to incorrect input validation, there is a heap-based buffer overflow that can result in Denial of Service to all clients using the proxy. Severity is high due to this vulnerability occurring before normal security checks; any remote client that can reach the proxy port can trivially perform the attack via a crafted URI scheme.

cvss

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–7.5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.17.5highAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-787USprimaryCWE-20USCWE-787US

affected products (61)

Products and version ranges known to be affected.

Amazon Linux 2all versionscert_bundDEcpe:/o:amazon:linux_2:-
Debian Linuxall versionscert_bundDEcpe:/o:debian:debian_linux:-
Oracle Linuxall versionscert_bundDEcpe:/o:oracle:linux:-
Red Hat Enterprise Linuxall versionscert_bundDEcpe:/o:redhat:enterprise_linux:-
SUSE Linuxall versionscert_bundDEcpe:/o:suse:suse_linux:-
Ubuntu Linuxall versionscert_bundDEcpe:/o:canonical:ubuntu_linux:-
n/a n/a≤ n/aenisa_euvdEU
Canonical Ltd. Ubuntu≤ 16.04 LTSfstec_bduRU
Canonical Ltd. Ubuntu≤ 19.04fstec_bduRU
Canonical Ltd. Ubuntu≤ 18.04 LTSfstec_bduRU
Canonical Ltd. Ubuntu≤ 19.10fstec_bduRU
Fedora Project Fedora≤ 31fstec_bduRU
Fedora Project Fedora≤ 30fstec_bduRU
Novell Inc. HPE Helion Openstack≤ 8fstec_bduRU
Novell Inc. OpenSUSE Leap≤ 15.1fstec_bduRU
Novell Inc. OpenSUSE Leap≤ 15.0fstec_bduRU
Novell Inc. SUSE Enterprise Storage≤ 5fstec_bduRU
Novell Inc. SUSE Linux Enterprise Module for Server Applications≤ 15 SP1fstec_bduRU
Novell Inc. SUSE Linux Enterprise Module for Server Applications≤ 15fstec_bduRU
Novell Inc. SUSE Linux Enterprise Point of Sale≤ 12 SP2-CLIENTfstec_bduRU

showing 20 of 61

advisories (1)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2022-1592Squid: Mehrere Schwachstellen ermöglichen Umgehung von SicherheitsvorkehrungenDeutsch2019-11-10csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Squid ausnutzen, um Sicherheitsvorkehrungen zu umgehen.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cert_bund NVD CVE.org MITRE

published 2019-11-26modified 2026-06-17

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+16119 more

references (60)

External citations — patches, advisories, analysis.

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