mime_header.cc in Squid before 3.5.18 allows remote attackers to bypass intended same-origin restrictions and possibly conduct cache-poisoni
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.
- Published
- May 10, 2016
- Updated
- Jun 16, 2026
- EPSS
- 38.9% · 99th percentile
- CWE
- CWE-345
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Report tools
Action score
46
Plan
Add it to your regular patch cycle.
- CVSS
- 34 / 40 · 8.6 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 12 / 30 · 38.9%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| oracle | linux | cpe:2.3:o:oracle:linux |
| squid-cache | squid | cpe:2.3:a:squid-cache:squid |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux12.04
- canonical ubuntu linux14.04
- canonical ubuntu linux15.10
- canonical ubuntu linux16.04
- oracle linux6
- oracle linux7
- squid-cache squidup to 3.5.17 inclusive
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | squid | before 4.1-1 | 4.1-1 |
| Debian:7 | squid | before 2.7.STABLE9-4.1+deb7u2 | 2.7.STABLE9-4.1+deb7u2 |
| Debian:7 | squid3 | before 3.1.20-2.2+deb7u5 | 3.1.20-2.2+deb7u5 |
| Debian:8 | squid3 | before 3.4.8-6+deb8u3 | 3.4.8-6+deb8u3 |
| Red Hat:enterprise_linux:6::server | squid | before 7:3.1.23-16.el6_8.4 | 7:3.1.23-16.el6_8.4 |
| Red Hat:enterprise_linux:6::server | squid-debuginfo | before 7:3.1.23-16.el6_8.4 | 7:3.1.23-16.el6_8.4 |
| Red Hat:enterprise_linux:6::server | squid34 | before 7:3.4.14-9.el6_8.3 | 7:3.4.14-9.el6_8.3 |
| Red Hat:enterprise_linux:6::server | squid34-debuginfo | before 7:3.4.14-9.el6_8.3 | 7:3.4.14-9.el6_8.3 |
| Red Hat:enterprise_linux:7::server | squid | before 7:3.3.8-26.el7_2.3 | 7:3.3.8-26.el7_2.3 |
| Red Hat:enterprise_linux:7::server | squid-debuginfo | before 7:3.3.8-26.el7_2.3 | 7:3.3.8-26.el7_2.3 |
| Red Hat:enterprise_linux:7::server | squid-sysvinit | before 7:3.3.8-26.el7_2.3 | 7:3.3.8-26.el7_2.3 |
| SUSE:Linux Enterprise Server 11 SP4 | squid | before 2.7.STABLE5-2.12.29.1 | 2.7.STABLE5-2.12.29.1 |
| SUSE:Linux Enterprise Server 12 SP1 | squid | before 3.3.14-20.2 | 3.3.14-20.2 |
Same product
oracle: all recordsOther highest-scoring records for the same primary product.
- CVE-2016-5408Stack-based buffer overflow in the munge_other_line function in cachemgr.cgi in the squid package before 3.1.23-16.el6_8.6 in Red Hat Enterp40Plan
- CVE-2016-3587Unspecified vulnerability in Oracle Java SE 8u92 and Java SE Embedded 8u91 allows remote attackers to affect confidentiality, integrity, and40Plan
- CVE-2016-3606Unspecified vulnerability in Oracle Java SE 7u101 and 8u92 and Java SE Embedded 8u91 allows remote attackers to affect confidentiality, inte39Monitor
- CVE-2016-0778The (1) roaming_read and (2) roaming_write functions in roaming_common.c in the client in OpenSSH 5.x, 6.x, and 7.x before 7.1p2, when certa38Monitor
- CVE-2022-21505In the linux kernel, if IMA appraisal is used with the "ima_appraise=log" boot param, lockdown can be defeated with kexec on any machine whe26Monitor
- CVE-2022-21499KGDB and KDB allow read and write access to kernel memory, and thus should be restricted during lockdown.26Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:squid | 4.1-1 · Debian:12 | Package registry (OSV) |
| debian:squid3 | 3.1.20-2.2+deb7u5 · Debian:7 | Package registry (OSV) |
| red hat:squid | 7:3.1.23-16.el6_8.4 · Red Hat:enterprise_linux:6::server | Package registry (OSV) |
| red hat:squid-debuginfo | 7:3.1.23-16.el6_8.4 · Red Hat:enterprise_linux:6::server | Package registry (OSV) |
| red hat:squid-sysvinit | 7:3.3.8-26.el7_2.3 · Red Hat:enterprise_linux:7::server | Package registry (OSV) |
| red hat:squid34 | 7:3.4.14-9.el6_8.3 · Red Hat:enterprise_linux:6::server | Package registry (OSV) |
| red hat:squid34-debuginfo | 7:3.4.14-9.el6_8.3 · Red Hat:enterprise_linux:6::server | Package registry (OSV) |
| suse:squid | 3.3.14-20.2 · SUSE:Linux Enterprise Server 12 SP1 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- high · data or configuration can be modified
- Availability
- none
Impact can extend beyond the vulnerable component (scope changes).
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality impact
- None
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-345 · Insufficient Verification of Data AuthenticityCVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- JSON Hijacking (aka JavaScript Hijacking)CAPEC-111likelihood: High · High
- Cache PoisoningCAPEC-141likelihood: High · High
- DNS Cache PoisoningCAPEC-142likelihood: High · High
- Content SpoofingCAPEC-148likelihood: Medium · Medium
- Spoofing of UDDI/ebXML MessagesCAPEC-218Medium
- Application API Message Manipulation via Man-in-the-MiddleCAPEC-384Low
- Transaction or Event Tampering via Application API ManipulationCAPEC-385Medium
- Application API Navigation RemappingCAPEC-386Medium
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- lists.opensuse.org/opensuse-security-announce/2016-08/msg00010.html
- lists.opensuse.org/opensuse-security-announce/2016-08/msg00040.html
- lists.opensuse.org/opensuse-updates/2016-08/msg00069.html
- www.debian.org/security/2016/dsa-3625
- www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
- www.securitytracker.com/id/1035769
- www.squid-cache.org/Advisories/SQUID-2016_8.txt
- www.squid-cache.org/Versions/v3/3.1/changesets/SQUID-2016_8.patch
- www.squid-cache.org/Versions/v3/3.2/changesets/SQUID-2016_8.patch
- www.squid-cache.org/Versions/v3/3.3/changesets/SQUID-2016_8.patch
- www.squid-cache.org/Versions/v3/3.4/changesets/SQUID-2016_8.patch
- www.squid-cache.org/Versions/v3/3.5/changesets/SQUID-2016_8.patch
- www.ubuntu.com/usn/USN-2995-1
- access.redhat.com/errata/RHSA-2016:1138
- access.redhat.com/errata/RHSA-2016:1139
- access.redhat.com/errata/RHSA-2016:1140
- security.gentoo.org/glsa/201607-01
Vendor advisories and official records. Exploit/PoC links are deliberately left out.