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TelegramApplication

CVE-2020-12474

MEDIUM · 6.5 CVSS v3.1 Published 2020-05-01
Fix available
A fix is available. Upgrade to after 6.0.1 or later.
See remediation →
72/100
Remediation priority · Elevated
Remotely reachable No privileges

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
Telegram Desktop through 2.0.1, Telegram through 6.0.1 for Android, and Telegram through 6.0.1 for iOS allow an IDN Homograph attack via Punycode in a public URL or a group chat invitation URL.

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 confidence

Telegram Desktop and mobile apps fail to properly validate IDN (Internationalized Domain Name) URLs, allowing homograph attacks where malicious actors use lookalike characters from different scripts (e.g., Cyrillic 'а' instead of Latin 'a') encoded in Punycode. This enables phishing via deceptively similar URLs in public chats and group invitations.

MitigationImplement Punycode/IDN homograph detection and display warnings or block visually-spoofed URLs; consider using visual indicators for non-ASCII domains or restricting allowed character sets.

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
TelegramApplication
Affected:<= 6.0.1
Telegram DesktopApplication
Affected:<= 2.0.1

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
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

Work through these to decide whether this CVE applies to you.

  1. Check Telegram Desktop version
    Open Telegram Desktop, go to Help > About, or use the three-line menu to access Settings > About. Note the version number displayed.
    Affected if Version is 2.0.1 or lower
  2. Check Telegram mobile app version
    On mobile, open Telegram, go to Settings (gear icon) > About, or Settings > Help > About. Note the version number displayed.
    Affected if Version is 6.0.1 or lower (iOS or Android)
  3. Confirm URL handling capability
    Verify that the installed Telegram client can open and preview URLs in chats, as the vulnerability applies to how URLs are processed and displayed.
    Affected if The client processes and displays clickable URLs in chats or group invitations

You are affected if your Telegram version is 2.0.1 or lower (Desktop) or 6.0.1 or lower (mobile) and the app processes URLs, because the client does not validate IDN/homograph URLs properly.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to a release after 6.0.1
Interim mitigation

Implement Punycode/IDN homograph detection and display warnings or block visually-spoofed URLs; consider using visual indicators for non-ASCII domains or restricting allowed character sets.

Fix this in Telegram Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,880
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,808.

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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-2020-12474 in production — separate from our analysis above.

No notes yet

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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
  • No spam, self-promotion, credentials, or personal data