CVE catalog

CVE-2019-18676

squid affected and fixed versions

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.

Severity: Medium · CVSS 5.9CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: Nov 5, 2019, 12:00:00 AM UTC
Source: [NVD] · [CVE record]
EPSS: 9.18% · Oct 27, 2026

Projects and upstream resources

[squid][Source-reported homepage]

Reported versions and fixes

Each observation applies to its named package, distribution, and release. Distribution backports can fix a vulnerability while retaining an older upstream version number.

Distribution / release	Package	Version	Status	Source
Debiantrixie-security	squid	`6.13-2+deb13u2`	Fixed	[CVE-2019-18676]
Debiantrixie	squid	`4.9-1`	FixedDistribution-reported fixed boundary	[CVE-2019-18676]
Debiantrixie	squid	`6.13-2+deb13u3`	Fixed	[CVE-2019-18676]
Debiansid	squid	`4.9-1`	FixedDistribution-reported fixed boundary	[CVE-2019-18676]
Debiansid	squid	`7.7-1`	Fixed	[CVE-2019-18676]
Debianforky	squid	`4.9-1`	FixedDistribution-reported fixed boundary	[CVE-2019-18676]
Debianforky	squid	`7.7-1`	Fixed	[CVE-2019-18676]
Debianbookworm-security	squid	`5.7-2+deb12u6`	Fixed	[CVE-2019-18676]
Debianbookworm	squid	`4.9-1`	FixedDistribution-reported fixed boundary	[CVE-2019-18676]
Debianbookworm	squid	`5.7-2+deb12u5`	Fixed	[CVE-2019-18676]

Showing 10 fix observations. All 39 observations, including unknown and conflicting reports, are available below.

Provider details and historical evidence

Distribution / release	Package	Version	Status	Source
Debianbookworm	squid	`4.9-1`	FixedDistribution-reported fixed boundary	[CVE-2019-18676]
Debianbookworm	squid	`5.7-2+deb12u5`	Fixed	[CVE-2019-18676]
Debianbookworm-security	squid	`5.7-2+deb12u6`	Fixed	[CVE-2019-18676]
Debianforky	squid	`4.9-1`	FixedDistribution-reported fixed boundary	[CVE-2019-18676]
Debianforky	squid	`7.7-1`	Fixed	[CVE-2019-18676]
Debiansid	squid	`4.9-1`	FixedDistribution-reported fixed boundary	[CVE-2019-18676]
Debiansid	squid	`7.7-1`	Fixed	[CVE-2019-18676]
Debiantrixie	squid	`4.9-1`	FixedDistribution-reported fixed boundary	[CVE-2019-18676]
Debiantrixie	squid	`6.13-2+deb13u3`	Fixed	[CVE-2019-18676]
Debiantrixie-security	squid	`6.13-2+deb13u2`	Fixed	[CVE-2019-18676]
Ubuntu16.04	squid3	`3.3.8-1ubuntu16`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.3.8-1ubuntu17`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu6`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7.1`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7.10`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7.11`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7.12`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7.2`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7.3`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7.4`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7.5`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7.6`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7.7`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7.8`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu16.04	squid3	`3.5.12-1ubuntu7.9`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu18.04	squid3	`3.5.23-5ubuntu1`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu18.04	squid3	`3.5.23-5ubuntu2`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu18.04	squid3	`3.5.27-1ubuntu1`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu18.04	squid3	`3.5.27-1ubuntu1.1`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu18.04	squid3	`3.5.27-1ubuntu1.2`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu18.04	squid3	`3.5.27-1ubuntu1.3`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu18.04	squid3	`3.5.27-1ubuntu1.4`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu18.04	squid3	`3.5.27-1ubuntu1.5`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu18.04	squid3	`3.5.27-1ubuntu1.6`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu18.04	squid3	`3.5.27-1ubuntu1.7`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu20.04	squid	`4.8-1ubuntu2`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu20.04	squid	`4.8-1ubuntu3`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC
Ubuntu20.04	squid	`4.9-2ubuntu1`	UnknownSource applicability is not established	[UBUNTU-CVE-2019-18676]Feb 4, 2026, 3:33:32 AM UTC

Original provider fields

{
  "package_releases": [
    {
      "name": "squid",
      "status": "fixed",
      "release": "sid",
      "version": "7.7-1"
    },
    {
      "name": "squid",
      "status": "fixed",
      "release": "forky",
      "version": "7.7-1"
    },
    {
      "name": "squid",
      "status": "fixed",
      "release": "trixie",
      "version": "6.13-2+deb13u3"
    },
    {
      "name": "squid",
      "status": "fixed",
      "release": "trixie-security",
      "version": "6.13-2+deb13u2"
    },
    {
      "name": "squid",
      "status": "fixed",
      "release": "bookworm",
      "version": "5.7-2+deb12u5"
    },
    {
      "name": "squid",
      "status": "fixed",
      "release": "bookworm-security",
      "version": "5.7-2+deb12u6"
    }
  ],
  "fixed_versions": [
    {
      "bug": null,
      "name": "squid",
      "type": "source",
      "origin": null,
      "release": "sid",
      "urgency": "not yet assigned",
      "fixed_version": "4.9-1"
    },
    {
      "bug": null,
      "name": "squid",
      "type": "source",
      "origin": null,
      "release": "forky",
      "urgency": "not yet assigned",
      "fixed_version": "4.9-1"
    },
    {
      "bug": null,
      "name": "squid",
      "type": "source",
      "origin": null,
      "release": "trixie",
      "urgency": "not yet assigned",
      "fixed_version": "4.9-1"
    },
    {
      "bug": null,
      "name": "squid",
      "type": "source",
      "origin": null,
      "release": "bookworm",
      "urgency": "not yet assigned",
      "fixed_version": "4.9-1"
    }
  ],
  "distribution_packages": [
    {
      "name": "squid3",
      "distro": "ubuntu",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.5.12-1ubuntu7.12"
            }
          ]
        }
      ],
      "release": "16.04",
      "versions": [
        "3.3.8-1ubuntu16",
        "3.3.8-1ubuntu17",
        "3.5.12-1ubuntu6",
        "3.5.12-1ubuntu7",
        "3.5.12-1ubuntu7.1",
        "3.5.12-1ubuntu7.2",
        "3.5.12-1ubuntu7.3",
        "3.5.12-1ubuntu7.4",
        "3.5.12-1ubuntu7.5",
        "3.5.12-1ubuntu7.6",
        "3.5.12-1ubuntu7.7",
        "3.5.12-1ubuntu7.8",
        "3.5.12-1ubuntu7.9",
        "3.5.12-1ubuntu7.10",
        "3.5.12-1ubuntu7.11"
      ],
      "ecosystem": "deb",
      "provider_url": "https://osv.dev/vulnerability/UBUNTU-CVE-2019-18676",
      "fixed_version": "3.5.12-1ubuntu7.12",
      "provider_source": "pypi",
      "provider_record_id": "UBUNTU-CVE-2019-18676",
      "provider_updated_at": "2026-02-04T03:33:32.728794Z",
      "applicability_unknown": true
    },
    {
      "name": "squid3",
      "distro": "ubuntu",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.5.27-1ubuntu1.7"
            }
          ]
        }
      ],
      "release": "18.04",
      "versions": [
        "3.5.23-5ubuntu1",
        "3.5.23-5ubuntu2",
        "3.5.27-1ubuntu1",
        "3.5.27-1ubuntu1.1",
        "3.5.27-1ubuntu1.2",
        "3.5.27-1ubuntu1.3",
        "3.5.27-1ubuntu1.4",
        "3.5.27-1ubuntu1.5",
        "3.5.27-1ubuntu1.6"
      ],
      "ecosystem": "deb",
      "provider_url": "https://osv.dev/vulnerability/UBUNTU-CVE-2019-18676",
      "fixed_version": "3.5.27-1ubuntu1.7",
      "provider_source": "pypi",
      "provider_record_id": "UBUNTU-CVE-2019-18676",
      "provider_updated_at": "2026-02-04T03:33:32.728794Z",
      "applicability_unknown": true
    },
    {
      "name": "squid",
      "distro": "ubuntu",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.9-2ubuntu1"
            }
          ]
        }
      ],
      "release": "20.04",
      "versions": [
        "4.8-1ubuntu2",
        "4.8-1ubuntu3"
      ],
      "ecosystem": "deb",
      "provider_url": "https://osv.dev/vulnerability/UBUNTU-CVE-2019-18676",
      "fixed_version": "4.9-2ubuntu1",
      "provider_source": "pypi",
      "provider_record_id": "UBUNTU-CVE-2019-18676",
      "provider_updated_at": "2026-02-04T03:33:32.728794Z",
      "applicability_unknown": true
    }
  ]
}

OpenFactory catalog packages

Matching against OpenFactory catalog package versions is in progress.

[Debian 12 (Bookworm)]

[squid]Unknown
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squid-cgi]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squidclient]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squid-common]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · all · bookworm
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · all · bookworm
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · all · bookworm-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · all · bookworm-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squid-openssl]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squid-purge]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12

[Debian 13 (Trixie)]

[squid]Unknown
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
[squid-cgi]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
[squidclient]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
[squid-common]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · all · trixie
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · all · trixie
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · all · trixie-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · all · trixie-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
[squid-openssl]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
[squid-purge]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.9-1
  dsa · squid · debian · 13

Observed: Oct 23, 2026, 5:42:01 PM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]