squid: Cross-Site Request Forgery issue in HTTP Request processing
Published Nov 26, 2019
6.1
MEDIUMCVSS 3.1
EPSS 7.24%
Description
An issue was discovered in Squid 3.x and 4.x through 4.8 when the append_domain setting is used (because the appended characters do not properly interact with hostname length restrictions). Due to incorrect message processing, it can inappropriately redirect traffic to origins it should not be delivered to.
Affected products
No data.
Configuration 1
- ≥ 2.0 · ≤ 2.7
- ≥ 3.0 · ≤ 3.5.28
- ≥ 4.0 · ≤ 4.8
- 2.7
- 2.7
- 2.7
- 2.7
- 2.7
- 2.7
- 2.7
- 2.7
Configuration 2
- 16.04
- 18.04
- 19.04
- 19.10
Configuration 3
- 30
- 31
No data.
Red Hat Enterprise Linux 8
squid:4-8030020200828070549.30b713e6
Fixed · RHSA-2020:4743
Red Hat Enterprise Linux 5
squid
Out of support scope
Red Hat Enterprise Linux 6
squid
Out of support scope
Red Hat Enterprise Linux 6
squid34
Out of support scope
Red Hat Enterprise Linux 7
squid
Will not fix
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 8 | squid:4-8030020200828070549.30b713e6 | Fixed | RHSA-2020:4743 |
| Red Hat Enterprise Linux 5 | squid | Out of support scope | n/a |
| Red Hat Enterprise Linux 6 | squid | Out of support scope | n/a |
| Red Hat Enterprise Linux 6 | squid34 | Out of support scope | n/a |
| Red Hat Enterprise Linux 7 | squid | Will not fix | n/a |
No package ranges for this CVE.
Remediation
Red Hat mitigation
As per upstream: Remove append_domain configuration settings from squid.conf. The append_domain feature is redundant when /etc/resolv.conf is used to determine hostnames. However, please note that use of /etc/resolv.conf may require removal of dns_nameservers and other redundant DNS directives.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
AV:N/AC:M/Au:N/C:P/I:P/A:N
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 4, 2026.
Score over time
2021-2026- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (31 key points)
Flat stretches are collapsed. Showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 4, 2026 | 7.24% (0.07239) | 94.15th | v5 (v2026.06.15) |
| Jun 15, 2026 | 7.24% (0.07239) | 93.51th | v5 (v2026.06.15) |
| Nov 21, 2025 | 4.21% (0.04214) | 88.27th | v4 (v2025.03.14) |
| Nov 18, 2025 | 1.69% (0.01690) | 80.73th | v4 (v2025.03.14) |
| Sep 5, 2025 | 4.14% (0.04138) | 88.20th | v4 (v2025.03.14) |
| Sep 1, 2025 | 2.38% (0.02377) | 84.46th | v4 (v2025.03.14) |
| Aug 7, 2025 | 4.59% (0.04594) | 88.81th | v4 (v2025.03.14) |
| Aug 1, 2025 | 3.39% (0.03386) | 87.02th | v4 (v2025.03.14) |
| Apr 7, 2025 | 4.94% (0.04940) | 88.69th | v4 (v2025.03.14) |
| Apr 6, 2025 | 9.65% (0.09652) | 92.17th | v4 (v2025.03.14) |
| Apr 5, 2025 | 10.71% (0.10706) | 92.66th | v4 (v2025.03.14) |
| Apr 2, 2025 | 9.65% (0.09652) | 92.17th | v4 (v2025.03.14) |
| Mar 31, 2025 | 10.71% (0.10706) | 92.64th | v4 (v2025.03.14) |
| Mar 30, 2025 | 9.65% (0.09652) | 92.15th | v4 (v2025.03.14) |
| Mar 29, 2025 | 11.94% (0.11937) | 89.57th | v4 (v2025.03.14) |
| Mar 17, 2025 | 9.65% (0.09652) | 92.32th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.38% (0.00379) | 73.77th | v3 (v2023.03.01) |
| Mar 21, 2024 | 0.40% (0.00399) | 73.08th | v3 (v2023.03.01) |
| Feb 8, 2024 | 0.40% (0.00405) | 73.04th | v3 (v2023.03.01) |
| Nov 8, 2023 | 0.40% (0.00405) | 70.78th | v3 (v2023.03.01) |
| Sep 30, 2023 | 0.31% (0.00311) | 66.52th | v3 (v2023.03.01) |
| Apr 15, 2023 | 0.32% (0.00320) | 66.07th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.37% (0.00368) | 68.22th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.54% (0.01537) | 74.52th | v2 (v2022.01.01) |
| Feb 23, 2023 | 1.54% (0.01537) | 74.48th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.54% (0.01537) | 72.41th | v2 (v2022.01.01) |
| Feb 4, 2022 | 11.61% (0.11613) | 88.84th | v2 (v2022.01.01) |
| Feb 3, 2022 | 10.22% (0.10225) | 87.52th | v1 |
| Jan 6, 2022 | 10.22% (0.10225) | 87.37th | v1 |
| Sep 1, 2021 | 2.48% (0.02476) | 78.74th | v1 |
| Apr 14, 2021 | 2.48% (0.02476) | 0.00th | v1 |
References (15)
- http://www.squid-cache.org/Advisories/SQUID-2019_9.txt x_refsource_CONFIRMThird Party Advisory
- http://www.squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-e5f1813a674848dde570f7920873e1071f96e0b4.patch x_refsource_CONFIRMRelease Notes
- http://www.squid-cache.org/Versions/v4/changesets/squid-4-36492033ea4097821a4f7ff3ddcb971fbd1e8ba0.patch x_refsource_CONFIRMRelease Notes
- https://access.redhat.com/security/cve/CVE-2019-18677 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1770365 Issue Tracking
- https://bugzilla.suse.com/show_bug.cgi?id=1156328 x_refsource_CONFIRMIssue TrackingThird Party Advisory
- https://github.com/squid-cache/squid/pull/427 x_refsource_MISCPatchThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2019/12/msg00011.html mailing-listx_refsource_MLISTThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html mailing-listx_refsource_MLIST
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MTM74TU2BSLT5B3H4F3UDW53672NVLMC/ vendor-advisoryx_refsource_FEDORA
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UEMOYTMCCFWK5NOXSXEIH5D2VGWVXR67/ vendor-advisoryx_refsource_FEDORA
- https://nvd.nist.gov/vuln/detail/CVE-2019-18677
- https://usn.ubuntu.com/4213-1/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2019-18677
- https://www.debian.org/security/2020/dsa-4682 vendor-advisoryx_refsource_DEBIAN
Change history (0)
No recorded changes yet.