Debian LinuxOperating system · Debian

CVE-2019-8921

MEDIUM · 6.5 CVSS v3.1 Published 2021-11-29
Fix available
A fix is available. Upgrade to after 5.48 or later.
See remediation →
70/100
Remediation priority · Elevated
Public exploit No privileges Zero-click Patch available

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
An issue was discovered in bluetoothd in BlueZ through 5.48. The vulnerability lies in the handling of a SVC_ATTR_REQ by the SDP implementation. By crafting a malicious CSTATE, it is possible to trick the server into returning more bytes than the buffer actually holds, resulting in leaking arbitrary heap data. The root cause can be found in the function service_attr_req of sdpd-request.c. The server does not check whether the CSTATE data is the same in consecutive requests, and instead simply trusts that it is the same.

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

A detailed technical summary for this CVE is being prepared.

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:= 10.0
BluezApplication
Affected:<= 5.48

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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 · scoped
Upgrade available Upgrade to a release after 5.48
Vendor patch ssd-disclosure.com →
Recommended fix Moderate confidence

BlueZ 5.50 or later (Debian 10 security updates include patches for this issue)

  1. 1. Identify the BlueZ version currently installed: dpkg -l | grep bluez or bluetoothd --version
  2. 2. For Debian 10 (Buster), check for updated packages: apt-get update && apt-cache policy bluez
  3. 3. Apply the security update: apt-get install --only-upgrade bluez
  4. 4. Restart the bluetooth service: systemctl restart bluetooth
  5. 5. Verify the new version is installed and the service is running: dpkg -l | grep bluez && systemctl status bluetooth

Generated from the published advisory — verify against the referenced sources before acting.

We can identify the exact fixed release, upgrade, and verify it in staging — typical engagement from $1,600. Get the upgrade done

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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-2019-8921 in production — separate from our analysis above.

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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
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