HIGH
squid: Header Smuggling issue in HTTP Request processing
Published May 10, 2016
8.6
HIGHCVSS 3.0
EPSS 38.89%
Description
mime_header.cc in Squid before 3.5.18 allows remote attackers to bypass intended same-origin restrictions and possibly conduct cache-poisoning attacks via a crafted HTTP Host header, aka a "header smuggling" issue.
Affected products
No data.
Configuration 2
- ≤ 3.5.17
Configuration 3
OR
- 12.04
- 14.04
- 15.10
- 16.04
No data.
Red Hat Enterprise Linux 6
squid-7:3.1.23-16.el6_8.4
Fixed · RHSA-2016:1138
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
Will not fix
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | squid-7:3.1.23-16.el6_8.4 | Fixed | RHSA-2016:1138 |
| 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 | Will not fix | 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.
8.6 HIGH NVD
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Changed
Confidentiality Impact None
Integrity Impact High
Availability Impact None
5.0 MEDIUM NVD
AV:N/AC:L/Au:N/C:N/I:P/A:N
Access Vector Network
Access Complexity Low
Authentication None
Confidentiality Impact None
Integrity Impact Partial
Availability Impact None
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
38.89% 0.38893
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
EPSS probability 0.38893
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 (23 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 38.89% (0.38893) | 98.55th | v5 (v2026.06.15) |
| Jun 15, 2026 | 39.15% (0.39152) | 98.41th | v5 (v2026.06.15) |
| Feb 18, 2026 | 68.86% (0.68860) | 98.58th | v4 (v2025.03.14) |
| Dec 28, 2025 | 73.39% (0.73388) | 98.75th | v4 (v2025.03.14) |
| Dec 27, 2025 | 40.57% (0.40573) | 97.23th | v4 (v2025.03.14) |
| Oct 28, 2025 | 73.39% (0.73388) | 98.73th | v4 (v2025.03.14) |
| Oct 27, 2025 | 40.57% (0.40573) | 97.20th | v4 (v2025.03.14) |
| Oct 1, 2025 | 73.39% (0.73388) | 98.76th | v4 (v2025.03.14) |
| Aug 20, 2025 | 40.57% (0.40573) | 97.25th | v4 (v2025.03.14) |
| Aug 19, 2025 | 43.66% (0.43661) | 97.42th | v4 (v2025.03.14) |
| Jul 30, 2025 | 40.57% (0.40573) | 97.23th | v4 (v2025.03.14) |
| Jun 19, 2025 | 73.39% (0.73388) | 98.71th | v4 (v2025.03.14) |
| Mar 30, 2025 | 62.49% (0.62491) | 98.22th | v4 (v2025.03.14) |
| Mar 29, 2025 | 60.84% (0.60842) | 97.56th | v4 (v2025.03.14) |
| Mar 17, 2025 | 62.49% (0.62491) | 98.20th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.31% (0.00307) | 70.73th | v3 (v2023.03.01) |
| May 5, 2024 | 0.31% (0.00307) | 69.74th | v3 (v2023.03.01) |
| Feb 8, 2024 | 0.37% (0.00372) | 71.88th | v3 (v2023.03.01) |
| Sep 17, 2023 | 0.37% (0.00372) | 69.37th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.53% (0.00527) | 73.41th | 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) |
Weaknesses (2)
References (21)
- 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/1035769 vdb-entryx_refsource_SECTRACKThird Party Advisory
- http://www.squid-cache.org/Advisories/SQUID-2016_8.txt x_refsource_CONFIRMVendor Advisory
- http://www.squid-cache.org/Versions/v3/3.1/changesets/SQUID-2016_8.patch x_refsource_CONFIRMPatch
- http://www.squid-cache.org/Versions/v3/3.2/changesets/SQUID-2016_8.patch x_refsource_CONFIRMPatch
- http://www.squid-cache.org/Versions/v3/3.3/changesets/SQUID-2016_8.patch x_refsource_CONFIRMPatch
- http://www.squid-cache.org/Versions/v3/3.4/changesets/SQUID-2016_8.patch x_refsource_CONFIRMPatch
- http://www.squid-cache.org/Versions/v3/3.5/changesets/SQUID-2016_8.patch x_refsource_CONFIRMPatch
- http://www.ubuntu.com/usn/USN-2995-1 vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://access.redhat.com/errata/RHSA-2016:1138 vendor-advisoryx_refsource_REDHAT
- 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-2016-4554 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1334241 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2016-4554
- https://security.gentoo.org/glsa/201607-01 vendor-advisoryx_refsource_GENTOO
- https://www.cve.org/CVERecord?id=CVE-2016-4554
Change history (0)
No recorded changes yet.
Sources
CVE.org / MITRE
Status PUBLISHED
Assigner mitre
Published May 10, 2016
Updated Aug 6, 2024
Reserved May 6, 2016
Link CVE-2016-4554
CISA Vulnrichment
Updated n/a