Ubuntu LinuxOperating system · Canonical
CVE-2022-28655
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 · uneditedis_closing_session() allows users to create arbitrary tcp dbus connections
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 · moderate confidenceThe is_closing_session() function in D-Bus contains a vulnerability that improperly validates session closure requests, allowing unprivileged users to establish arbitrary TCP-based D-Bus connections. This bypasses the default security model that restricts D-Bus to local Unix domain sockets, potentially enabling local privilege escalation or remote attacks depending on system configuration.
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
= 18.04= 20.04= 21.10= 22.04< 2.21.0CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
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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Check Ubuntu versionRun 'lsb_release -r' or check /etc/lsb-release to identify the installed Ubuntu versionAffected if The system is running Ubuntu 18.04, 20.04, 21.10, or 22.04
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Check Apport versionRun 'apt-cache policy apport' or 'python3 -c "import apport; print(apport.__version__)"' to determine installed Apport versionAffected if Apport version is less than 2.21.0
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Verify D-Bus TCP listener statusCheck D-Bus configuration files in /etc/dbus-1/ and run 'dbus-send --system --print-reply --dest=org.freedesktop.DBus /org/freedesktop/DBus org.freedesktop.DBus.ListActivatableNames' to enumerate available services, then inspect any listening network sockets with 'ss -tlnp | grep dbus' or 'netstat -tlnp | grep dbus'Affected if The D-Bus daemon is configured to listen on TCP sockets (typically port 55556 or similar) rather than Unix domain sockets only
A system is affected if it runs Ubuntu 18.04, 20.04, 21.10, or 22.04 (or Apport < 2.21.0 if installed) AND has D-Bus TCP listener enabled, allowing unprivileged users to establish TCP-based D-Bus connections.
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.
dbcve · scoped2.21.0
Restrict D-Bus daemon to Unix socket-only mode and disable TCP listener configuration. Apply vendor patches when available. If TCP D-Bus is required, implement strict access control policies and firewall rules.
Apport >= 2.21.0 (via Ubuntu security updates)
- Update package lists: sudo apt-get update
- Upgrade Apport to the fixed version: sudo apt-get install --upgrade apport
- Verify the installed version matches or exceeds 2.21.0: apport-cli --version or dpkg -s apport | grep Version
- Restart any running Apport services or log out/in to ensure the new version is fully active
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Ubuntu Linux
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2022-28655 — 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-2022-28655 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
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