dbcve.org
Debian LinuxOperating system · Debian

CVE-2017-7656

HIGH · 7.5 CVSS v3.0 Published 2018-06-26
Fix available
A fix is available. Upgrade to 9.3.24 / 9.4.11 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In Eclipse Jetty, versions 9.2.x and older, 9.3.x (all configurations), and 9.4.x (non-default configuration with RFC2616 compliance enabled), HTTP/0.9 is handled poorly. An HTTP/1 style request line (i.e. method space URI space version) that declares a version of HTTP/0.9 was accepted and treated as a 0.9 request. If deployed behind an intermediary that also accepted and passed through the 0.9 version (but did not act on it), then the response sent could be interpreted by the intermediary as HTTP/1 headers. This could be used to poison the cache if the server allowed the origin client to generate arbitrary content in the response.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Eclipse Jetty accepts HTTP/1-style request lines that declare a version of HTTP/0.9 and processes them as 0.9 requests. When deployed behind intermediaries that pass through the 0.9 version, the response can be misinterpreted as HTTP/1 headers by the intermediary, enabling cache poisoning attacks if the origin server allows clients to control response content.

MitigationDisable RFC2616 compliance mode in Jetty 9.4.x configurations, or upgrade to Jetty versions 9.2.26+, 9.3.11+, or 9.4.5+ which contain the fix. Implement cache validation mechanisms (ETags/Last-Modified) to prevent poisoning.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Debian LinuxOperating system
Affected:= 9.0
JettyApplication
Affected:<= 9.2.26>= 9.3.0, < 9.3.24>= 9.4.0, < 9.4.11

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Jetty version
    Run 'java -jar jetty-version.jar' or check the jetty-version module, or examine the jetty-distribution JAR/WAR file name, or check the startup logs for the version string
    Affected if The version is <= 9.2.26, OR between 9.3.0 and 9.3.23 inclusive, OR between 9.4.0 and 9.4.10 inclusive, OR the Debian package version is 9.0 on Debian Linux
  2. Check RFC2616 compliance mode configuration
    Examine the start.ini or start.d configuration files for 'org.eclipse.jetty.http.HttpCompliance' or 'org.eclipse.jetty.server.HttpCompliance' settings. Look for values like 'RFC2616' or 'LEGACY'
    Affected if The configuration explicitly sets compliance to RFC2616 or allows 0.9-style requests (legacy/violation mode) and the Jetty version is within the affected range
  3. Verify if Jetty is behind an intermediary
    Review network architecture documentation or examine proxy configuration files (e.g., nginx, Apache httpd, Varnish, Squid) to determine if HTTP responses from Jetty pass through a caching proxy or other intermediary before reaching clients
    Affected if Jetty is deployed behind a caching proxy or intermediary that processes responses as HTTP/1 and may misinterpret 0.9-style responses as HTTP/1 headers

You are affected if your Jetty version is within the vulnerable ranges AND RFC2616 compliance mode (or equivalent 0.9 request handling) is enabled AND Jetty sits behind a caching intermediary that could misinterpret the response format.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 9.3.24 / 9.4.11 or later
Fixed in 9.3.249.4.11
Interim mitigation

Disable RFC2616 compliance mode in Jetty 9.4.x configurations, or upgrade to Jetty versions 9.2.26+, 9.3.11+, or 9.4.5+ which contain the fix. Implement cache validation mechanisms (ETags/Last-Modified) to prevent poisoning.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,760
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,416.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2017-7656 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2017-7656 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data