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WireApplication

CVE-2020-27853

CRITICAL · 9.8 CVSS v3.1 Published 2020-10-27
Fix available
A fix is available. Upgrade to 3.21.2936 / 3.21.3932 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click

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
Wire before 2020-10-16 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a format string. This affects Wire AVS (Audio, Video, and Signaling) 5.3 through 6.x before 6.4, the Wire Secure Messenger application before 3.49.918 for Android, and the Wire Secure Messenger application before 3.61 for iOS. This occurs via the value parameter to sdp_media_set_lattr in peerflow/sdp.c.

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

A detailed technical summary for this CVE is being prepared.

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
WireApplication
Affected:< 3.21.2936< 3.21.3932< 3.21.3959
Wire Audio\, Video\, And SignalingApplication
Affected:>= 5.3, < 6.4
Wire Secure MessengerApplication
Affected:< 3.49.918< 3.61

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
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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 · scoped
Upgrade available Upgrade to 3.21.2936 / 3.21.3932 / 3.21.3959 or later
Fixed in 3.21.29363.21.39323.21.3959
Recommended fix High confidence

Wire client: 3.21.2936/3.21.3932/3.21.3959 or later; Wire AVS: 6.4 or later; Wire Secure Messenger Android: 3.49.918 or later; Wire Secure Messenger iOS: 3.61 or later

  1. Identify which Wire product is in use: Wire desktop client, Wire AVS (Audio/Video/Signaling), or Wire Secure Messenger (Android/iOS)
  2. For Wire desktop client: Check version - upgrade to 3.21.2936, 3.21.3932, 3.21.3959 or later
  3. For Wire AVS: Upgrade to version 6.4 or later
  4. For Wire Secure Messenger Android: Upgrade to version 3.49.918 or later
  5. For Wire Secure Messenger iOS: Upgrade to version 3.61 or later
  6. Verify the upgrade was successful and the application starts without format string errors

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,300. Get the upgrade done

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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-2020-27853 in production — separate from our analysis above.

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What this is

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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