Debian LinuxOperating system · Debian
CVE-2021-32917
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 · uneditedAn issue was discovered in Prosody before 0.11.9. The proxy65 component allows open access by default, even if neither of the users has an XMPP account on the local server, allowing unrestricted use of the server's bandwidth.
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 confidenceThe proxy65 file transfer proxy component in Prosody XMPP server versions before 0.11.9 has a default-access configuration flaw that permits relay connections from any remote user, regardless of whether they possess local XMPP accounts. This allows external parties to abuse the server's bandwidth by using it as an open proxy.
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
= 9.0= 10.0
FedoraOperating system
= 32= 33= 34< 0.11.9CVSS 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
- None
- Integrity
- None
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Check Prosody versionRun `prosodyctl version` or check package manager: `dpkg -l prosody` (Debian) or `rpm -q prosody` (Fedora)Affected if Version is less than 0.11.9 (e.g., 0.11.8, 0.11.7, etc.) or if the version cannot be determined
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Verify proxy65 module is loadedCheck Prosody config file (typically /etc/prosody/prosody.cfg.lua) for `modules_enabled` section or look for 'proxy65' in the configurationAffected if proxy65 appears in modules_enabled list or is otherwise enabled in the configuration
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Inspect proxy65 access control settingsLook for proxy65 component configuration block in prosody.cfg.lua. Check for `proxy65_acl` or `allow` / `deny` rules restricting relay access to authenticated users onlyAffected if No access control rules are defined, or the configuration permits anonymous/unauthenticated relay connections (no restrictions on who can use the proxy)
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Check for open relay configurationSearch config for lines like `proxy65_acl = { "*" }` or similar wildcard patterns that grant access to all users including external onesAffected if The proxy65 component allows connections from any remote user without requiring local XMPP authentication
You are affected if Prosody version is below 0.11.9 AND the proxy65 module is enabled WITHOUT proper access control restrictions limiting relay usage to authenticated local users.
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 data0.11.9
Configure the proxy65 component to restrict access to authenticated local users only by adding appropriate allow/deny rules in the Prosody configuration, or disable the component if not required.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-32917 — 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-2021-32917 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
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