CVE-2020-15853
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 · uneditedsupybot-fedora implements the command 'refresh', that refreshes the cache of all users from FAS. This takes quite a while to run, and zodbot stops responding to requests during this time.
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 'refresh' command in supybot-fedora synchronously fetches user data from the Fedora Account System (FAS), blocking the bot's event loop. During this time, zodbot cannot process any other requests, resulting in a denial of service condition for legitimate users.
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 dataall versionsCVSS 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.
-
Verify supybot-fedora plugin installationCheck for the presence of the supybot-fedora plugin in the bot's plugin directory or loaded plugins list. Look for files related to fedora, fas, or supybot-fedora in the bot's configuration.Affected if The supybot-fedora plugin is installed or loaded in the bot environment
-
Confirm the 'refresh' command is accessibleCheck if the 'refresh' command is exposed by the fedora plugin. This may be visible in the bot's help system, command list, or plugin metadata.Affected if The 'refresh' command is available and can be invoked by users or administrators
-
Identify if synchronous FAS fetching is occurringReview the plugin's source code or configuration for the refresh function implementation. Look for blocking HTTP calls to the Fedora Account System without async/await or threading mechanisms.Affected if The refresh command performs synchronous blocking network requests to FAS without async handling or timeouts
A user is affected if they have the supybot-fedora plugin loaded with the refresh command available, as the synchronous FAS fetching will block the bot's event loop when the command is invoked.
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 dataImplement asynchronous or background processing for the refresh operation, or add rate limiting and timeouts to prevent the refresh from blocking the bot entirely.
- Consultation2.0 h
- Implementation6.0 h
- Testing3.0 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 $3,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-15853 — 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-2020-15853 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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