KdelibsApplication · Kde

CVE-2009-2702

HIGH · 7.5 CVSS v2.0 Published 2009-09-08
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
KDE KSSL in kdelibs 3.5.4, 4.2.4, and 4.3 does not properly handle a '\0' character in a domain name in the Subject Alternative Name field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.

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

KDE KSSL in kdelibs versions 3.5.4, 4.2.4, and 4.3 fails to properly handle a null byte ('\0') in domain names within the X.509 Subject Alternative Name field. This allows attackers to craft certificates that appear valid for a target domain by truncating the domain name at the null byte, enabling man-in-the-middle attacks against SSL connections.

MitigationUpdate to patched versions of kdelibs (beyond 4.3) that properly validate and reject certificates with embedded null bytes in the SAN field, or upgrade to a modern KDE release.

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
KdelibsApplication
Affected:= 3.5.4= 4.2.4= 4.3

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
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial

AV:N/AC:L/Au:N/C:P/I:P/A:P

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 kdelibs version
    Run 'kde-config --version' or check the package manager for kdelibs version (e.g., dpkg -l kdelibs, rpm -qa | grep kdelibs)
    Affected if The version is 3.5.4, 4.2.4, or 4.3 exactly
  2. Confirm KDE SSL (KSSL) is in use
    Check if applications using KDE's SSL infrastructure are running. Look for processes like konqueror, kmail, or other KDE apps that make HTTPS connections. KSSL is the KDE SSL library used by KDE applications.
    Affected if KDE applications making SSL/TLS connections are in use on the system
  3. Verify SSL certificate validation occurs
    Check if the system uses KSSL for SSL certificate validation. This can be observed by testing SSL connections through KDE browsers or network applications, or by reviewing application SSL library usage.
    Affected if Applications rely on KSSL for validating SSL certificates from remote hosts

You are affected if your system has kdelibs version 3.5.4, 4.2.4, or 4.3 installed AND KDE applications use KSSL to validate SSL certificates for network connections.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update to patched versions of kdelibs (beyond 4.3) that properly validate and reject certificates with embedded null bytes in the SAN field, or upgrade to a modern KDE release.

Fix this in Kdelibs Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing5.0 h
  • Review / QA3.0 h
17.0 hours of engineering $2,970
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2009-2702 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2009-2702 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