CVE-2026-39087
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 · uneditedntfy before 2.22.0 allows SSRF because of an unanchored regular expression for web push endpoint URLs.
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 confidencentfy before 2.22.0 contains an SSRF vulnerability due to an unanchored regular expression used to validate web push endpoint URLs. An unanchored regex can match patterns anywhere in a string rather than requiring a full match, potentially allowing attackers to bypass validation and force the server to make requests to arbitrary URLs including internal infrastructure.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- Privileges
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
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 installed ntfy versionRun 'ntfy --version' or check the container image tag / binary version. If using a package manager, query the installed package version.Affected if Version is below 2.22.0 (e.g., 2.21.x, 2.20.x, etc.)
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Identify if web push is configuredInspect ntfy configuration files (default /etc/ntfy/config.yml or environment variables) for 'web-push' or 'webpush' settings. Check if any notification filters or attachments reference web push endpoints.Affected if Web push notification endpoints are defined in the ntfy configuration or attached to notification filters
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Verify the URL validation behaviorIf you have access to logs or can test, attempt to register a web push endpoint with a URL containing internal infrastructure patterns (e.g., 'http://localhost', 'http://192.168.x.x'). Observe if the request is blocked or accepted.Affected if URLs with internal hostnames or IP addresses are accepted by the validation without rejection
You are affected if ntfy version is below 2.22.0 AND web push notification endpoints are configured or can be added through the ntfy UI or API.
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 · scopedUpgrade ntfy to version 2.22.0 or later which contains a properly anchored regular expression for URL validation.
2.22.0
- Identify the currently running ntfy version (check via docker image tag, binary version, or package manager)
- Back up the ntfy configuration file and any persistent data
- Upgrade ntfy to version 2.22.0 or later
- Restart the ntfy service to apply the update
- Verify the new version is running (ntfy --version or equivalent)
- Test that web push endpoint functionality works correctly
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 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 $1,936.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-39087 — 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-2026-39087 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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- 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