squid: Cache poisoning issue in HTTP Request handling
Published May 10, 2016
8.6
HIGHCVSS 3.0
EPSS 79.97%
Description
client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host header when absolute-URI is provided, which allows remote attackers to conduct cache-poisoning attacks via an HTTP request.
Affected products
No data.
Configuration 1
- 12.04
- 14.04
- 15.10
- 16.04
Configuration 2
- ≤ 3.5.17
Configuration 3
- 4.0.1
- 4.0.2
- 4.0.3
- 4.0.4
- 4.0.5
- 4.0.6
- 4.0.7
- 4.0.8
- 4.0.9
No data.
Red Hat Enterprise Linux 6
squid34-7:3.4.14-9.el6_8.3
Fixed · RHSA-2016:1140
Red Hat Enterprise Linux 7
squid-7:3.3.8-26.el7_2.3
Fixed · RHSA-2016:1139
Red Hat Enterprise Linux 5
squid
Not affected
Red Hat Enterprise Linux 6
squid
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | squid34-7:3.4.14-9.el6_8.3 | Fixed | RHSA-2016:1140 |
| Red Hat Enterprise Linux 7 | squid-7:3.3.8-26.el7_2.3 | Fixed | RHSA-2016:1139 |
| Red Hat Enterprise Linux 5 | squid | Not affected | n/a |
| Red Hat Enterprise Linux 6 | squid | Not affected | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
AV:N/AC:L/Au:N/C:N/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 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (22 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 79.97% (0.79969) | 99.60th | v5 (v2026.06.15) |
| Jun 15, 2026 | 79.65% (0.79651) | 99.56th | v5 (v2026.06.15) |
| Dec 28, 2025 | 82.84% (0.82841) | 99.21th | v4 (v2025.03.14) |
| Dec 27, 2025 | 39.53% (0.39528) | 97.18th | v4 (v2025.03.14) |
| Oct 28, 2025 | 82.84% (0.82841) | 99.20th | v4 (v2025.03.14) |
| Oct 27, 2025 | 39.53% (0.39528) | 97.14th | v4 (v2025.03.14) |
| Oct 1, 2025 | 82.84% (0.82841) | 99.21th | v4 (v2025.03.14) |
| Aug 19, 2025 | 39.53% (0.39528) | 97.19th | v4 (v2025.03.14) |
| Jul 30, 2025 | 45.04% (0.45040) | 97.48th | v4 (v2025.03.14) |
| Mar 17, 2025 | 86.88% (0.86880) | 99.39th | v4 (v2025.03.14) |
| Feb 28, 2025 | 38.68% (0.38678) | 97.35th | v3 (v2023.03.01) |
| Dec 17, 2024 | 46.39% (0.46386) | 97.51th | v3 (v2023.03.01) |
| May 5, 2024 | 56.32% (0.56324) | 97.66th | v3 (v2023.03.01) |
| Jan 29, 2024 | 52.87% (0.52868) | 97.32th | v3 (v2023.03.01) |
| Dec 27, 2023 | 60.27% (0.60273) | 97.47th | v3 (v2023.03.01) |
| Oct 21, 2023 | 67.03% (0.67031) | 97.57th | v3 (v2023.03.01) |
| Sep 17, 2023 | 72.94% (0.72943) | 97.69th | v3 (v2023.03.01) |
| Aug 11, 2023 | 87.96% (0.87958) | 98.22th | v3 (v2023.03.01) |
| Mar 7, 2023 | 93.86% (0.93860) | 98.58th | v3 (v2023.03.01) |
| Mar 6, 2023 | 3.78% (0.03779) | 85.48th | v2 (v2022.01.01) |
| Apr 1, 2022 | 3.78% (0.03779) | 84.01th | v2 (v2022.01.01) |
| Feb 4, 2022 | 3.78% (0.03779) | 67.21th | v2 (v2022.01.01) |
References (17)
- http://bugs.squid-cache.org/show_bug.cgi?id=4501 x_refsource_CONFIRMVendor Advisory
- http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00010.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00040.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-updates/2016-08/msg00069.html vendor-advisoryx_refsource_SUSE
- http://www.debian.org/security/2016/dsa-3625 vendor-advisoryx_refsource_DEBIAN
- http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html x_refsource_CONFIRMThird Party Advisory
- http://www.securitytracker.com/id/1035768 vdb-entryx_refsource_SECTRACKThird Party Advisory
- http://www.squid-cache.org/Advisories/SQUID-2016_7.txt x_refsource_CONFIRMVendor Advisory
- http://www.squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-14039.patch x_refsource_CONFIRM
- http://www.ubuntu.com/usn/USN-2995-1 vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://access.redhat.com/errata/RHSA-2016:1139 vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2016:1140 vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2016-4553 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1334233 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2016-4553
- https://security.gentoo.org/glsa/201607-01 vendor-advisoryx_refsource_GENTOO
- https://www.cve.org/CVERecord?id=CVE-2016-4553
Change history (0)
No recorded changes yet.