CVE-2019-9970
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 · uneditedOpen Whisper Signal (aka Signal-Desktop) through 1.23.1 and the Signal Private Messenger application through 4.35.3 for Android are vulnerable to an IDN homograph attack when displaying messages containing URLs. This occurs because the application produces a clickable link even if (for example) Latin and Cyrillic characters exist in the same domain name, and the available font has an identical representation of characters from different alphabets.
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 confidenceSignal-Desktop (through 1.23.1) and Signal Android (through 4.35.3) fail to properly validate Internationalized Domain Names (IDN) in message URLs, allowing homograph attacks where visually identical characters from different scripts (e.g., Cyrillic 'a' vs Latin 'a') create deceptive links that appear legitimate to 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 data<= 4.35.3<= 1.23.1CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/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 Signal Desktop versionOpen Signal Desktop, click the three-dot menu (top left), select 'Settings', then scroll to the bottom where the version number is displayed under 'About Signal'. Alternatively, check the installed package metadata in your operating system's application manager.Affected if The version is 1.23.1 or lower (any version up to and including 1.23.1).
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Check Signal Android versionOpen the Google Play Store app, search for 'Signal Private Messenger', or open Signal Android, tap your profile icon (top right), scroll down to 'Advanced' and tap it, then look for the version number displayed at the bottom of the next screen.Affected if The version is 4.35.3 or lower (any version up to and including 4.35.3).
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Identify which platform is in useDetermine whether you primarily use Signal Desktop (Windows, macOS, or Linux) or Signal Android (mobile device). Both products are affected independently; you must check each installed platform.Affected if Either Signal Desktop version <= 1.23.1 OR Signal Android version <= 4.35.3 is installed on any device or machine you use.
You are affected if any installed instance of Signal Desktop is at version 1.23.1 or lower, OR any installed instance of Signal Android is at version 4.35.3 or lower.
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 IDN homograph protection by validating that domain names use a single script/alphabet or by displaying punycode representations to reveal the actual domain encoding.
- Consultation2.0 h
- Implementation4.0 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 $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-9970 — 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-2019-9970 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