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No exploitation reportedFix available

CVE-2019-18676

No exploitation reported by the sources we read.

  • Published2019-11-26
  • WeaknessCWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2019-11-2617:15CVE publishedNVD

Versions per branch

NVD
Canonical ubuntu linux
BranchAffectedFixed in
16.4= 16.04no fix published
18.4= 18.04no fix published
19.4= 19.04no fix published
19.10= 19.10no fix published
Debian debian linux
BranchAffectedFixed in
9.0= 9.0no fix published
10.0= 10.0no fix published
Fedoraproject fedora
BranchAffectedFixed in
30.x= 30no fix published
31.x= 31no fix published

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • libecapRocky Linux:8all versions · fixed in 0:1.0.1-2.module+el8.4.0+404+316a0dc5
  • libecapRed Hat:enterprise_linux:8::appstreamall versions · fixed in 0:1.0.1-2.module+el8.1.0+4044+36416a77and 3 other packages
  • libecapAlmaLinux:8all versions · fixed in 1.0.1-2.module_el8.6.0+2741+01592ae8and 1 other package
  • squidUbuntu:20.04:LTSall versions · fixed in 4.9-2ubuntu1
  • squidTuxCare:OracleLinux:6all versions · fixed in 7:3.1.23-30.el6.tuxcare.els17
  • squidTuxCare:CentOS:6all versions · fixed in 7:3.1.23-30.el6.tuxcare.els17
  • squidSUSE:OpenStack Cloud Crowbar 8all versions · fixed in 3.5.21-26.20.1
  • squidSUSE:OpenStack Cloud 8all versions · fixed in 3.5.21-26.20.1

32 more package ranges on OSV.dev

Vendor advisories

  • CVE-2019-18676 Red Hat Product Security30 products fixed · 8 known affected

    squid: Buffer overflow in URI processor

    squid as a component of Red Hat Enterprise Linux 6 · squid.src as a component of Red Hat Enterprise Linux 6 · squid34 as a component of Red Hat Enterprise Linux 6 · +5 more

  • RHSA-2020:4743 Red Hat Product Security30 products fixed

    Red Hat Security Advisory: squid:4 security, bug fix, and enhancement update

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2020:4743 · 30 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 After installing this update, the squid service will be restarted automatically.
  2. No fix planned, says the vendor Red Hat Product Security CVE-2019-18676 · 4 productsOut of support scope
  3. No fix planned, says the vendor Red Hat Product Security CVE-2019-18676 · 4 productsWill not fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2019-11-26
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-chw7-jm99-chw8

Frequently asked questions

What is CVE-2019-18676?

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.

Is CVE-2019-18676 actively exploited?

Active exploitation of CVE-2019-18676 has not been confirmed. Its EPSS score was 9.2% on 2026-11-09, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-18676?

CVE-2019-18676 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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