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Ubuntu LinuxOperating system · Canonical

CVE-2018-5175

MEDIUM · 6.1 CVSS v3.0 Published 2018-06-11
Fix available
A fix is available. Upgrade to 60.0 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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
A mechanism to bypass Content Security Policy (CSP) protections on sites that have a "script-src" policy of "'strict-dynamic'". If a target website contains an HTML injection flaw an attacker could inject a reference to a copy of the "require.js" library that is part of Firefox's Developer Tools, and then use a known technique using that library to bypass the CSP restrictions on executing injected scripts. This vulnerability affects Firefox < 60.

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

Firefox contains a Content Security Policy bypass vulnerability where an attacker with HTML injection capability can load require.js (from Firefox Developer Tools) and use it to execute arbitrary JavaScript despite CSP 'strict-dynamic' restrictions. The attack requires an existing HTML injection flaw on the target site.

MitigationUpgrade Firefox to version 60 or later. Additionally, remediate any HTML injection vulnerabilities in web applications to prevent the attack chain from being exploitable.

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
Ubuntu LinuxOperating system
Affected:= 14.04= 16.04= 17.10= 18.04
FirefoxWeb browser
Affected:< 60.0

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
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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. Check Firefox version installed
    Open Firefox, click the menu button, select Help > About Firefox. Alternatively, run 'firefox --version' from command line or check /usr/lib/firefox/firefox.sh for version string
    Affected if Firefox version is less than 60.0 (e.g., 59.x, 58.x, etc.)
  2. Verify Ubuntu package version
    Run 'dpkg -l firefox' or 'apt-cache policy firefox' to check the installed Firefox package version
    Affected if The installed firefox package version is lower than 60.0+bsn-0ubuntu0 or equivalent Firefox 60 release packages for Ubuntu
  3. Identify web applications with HTML injection risks
    Audit web applications for reflected/stored XSS or HTML injection vulnerabilities using manual testing or automated scanners
    Affected if Any web application accessible from the Firefox client contains exploitable HTML injection flaws that could inject a require.js script tag
  4. Check for CSP strict-dynamic policies
    Review web application CSP headers: look for 'strict-dynamic' directive in Content-Security-Policy header responses from target sites
    Affected if Target web applications enforce CSP with 'strict-dynamic' but the attacker can inject HTML (the bypass specifically evades strict-dynamic when require.js is loaded)

A user is affected if Firefox version 59 or earlier is installed AND they access web applications that have both CSP strict-dynamic policies AND HTML injection vulnerabilities exploitable from the browser context.

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 60.0 or later
Fixed in 60.0
Interim mitigation

Upgrade Firefox to version 60 or later. Additionally, remediate any HTML injection vulnerabilities in web applications to prevent the attack chain from being exploitable.

Fix this in Ubuntu Linux Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

Scan for this in your stack

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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-2018-5175 in production — separate from our analysis above.

No notes yet

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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