Debian LinuxOperating system · Debian
CVE-2016-7966
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 · uneditedThrough a malicious URL that contained a quote character it was possible to inject HTML code in KMail's plaintext viewer. Due to the parser used on the URL it was not possible to include the equal sign (=) or a space into the injected HTML, which greatly reduces the available HTML functionality. Although it is possible to include an HTML comment indicator to hide content.
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 confidenceKMail's plaintext viewer contains an HTML injection vulnerability where a malicious URL containing a quote character allows injection of HTML code. The URL parser's limitation prevents inclusion of the equal sign (=) or space characters, restricting available HTML functionality, though HTML comment indicators can be used to hide injected content.
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
= 8.0
FedoraOperating system
= 25<= 4.4.0= 12.0CVSS 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
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
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 checksWork through these to decide whether this CVE applies to you.
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Verify KMail is installedRun 'kmail --version' or check for KMail package via package manager (dpkg -l | grep kmail on Debian, rpm -qa | grep kmail on RHEL/SUSE)Affected if KMail is not installed - not affected. If installed, proceed to version check.
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Check installed KMail versionExecute 'kmail --version' or use package manager to query version (e.g., 'apt-cache policy kmail' on Debian, 'rpm -qi kdepim' on SUSE/Fedora)Affected if Version is 4.4.0 or lower - potentially affected. Versions above 4.4.0 are not in the affected range.
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Confirm operating system versionCheck OS release: 'cat /etc/os-release' or 'lsb_release -a' to identify if running Debian 8, Fedora 25, or SUSE 12.0Affected if Running Debian 8, Fedora 25, or SUSE 12.0 with KMail <= 4.4.0 - likely affected per advisory.
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Identify plaintext viewer configurationIn KMail, go to Settings > Configure KMail > Reader > General. Check 'Default view' setting for plaintext emailsAffected if Plaintext viewer is enabled as default - this is the vulnerable component where HTML injection can occur.
User is affected if running KMail version 4.4.0 or lower on Debian 8, Fedora 25, or SUSE 12.0, with the plaintext viewer enabled as the default email viewing mode.
Generated from the published advisory. Verify against your own configuration.
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 dataUpgrade KMail to a version that properly sanitizes URLs in the plaintext viewer, or implement input validation to escape or reject quote characters in URLs before rendering.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation4.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,040.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-7966 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2016-7966 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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