CVE-2026-126546: Viber for iOS through 29.4.0.24 Denial of Service via Malformed GIF

Q: Who is affected by this issue?

Viber for iOS installations running version 29.4.0.24 or earlier are affected when a user opens a specially crafted GIF received through the app.

Q: What does an attacker need to do to trigger the crash?

An attacker needs to send a GIF whose header specifies zero logical screen dimensions. The recipient must open the crafted GIF for Viber to process it and abort with SIGABRT.

Q: What is the impact of successful exploitation?

Successful exploitation crashes the Viber application, causing a denial of service. The provided data does not indicate confidentiality loss, integrity loss, or code execution.

Published Nov 11, 2026

Updated

Viber for iOS through 29.4.0.24 fails to validate the logical screen width and height in received GIF headers, allowing attackers to crash the app. Attackers can send a crafted GIF with zero dimensions that triggers an uncaught NSInternalInconsistencyException, aborting the app with SIGABRT when opened.

Affected Software

1 affected component

Viber Viber for iOS<=29.4.0.24

Event History

Nov 11, 2026

CVE Published

via MITRE·12:58 AM

Data Sourced

via MITRE·12:58 AM

DescriptionSeverityWeakness

Data Sourced

via NVD·01:17 AM

DescriptionSeverityWeakness

Frequently Asked Questions

Who is affected by this issue?

Viber for iOS installations running version 29.4.0.24 or earlier are affected when a user opens a specially crafted GIF received through the app.

What does an attacker need to do to trigger the crash?

An attacker needs to send a GIF whose header specifies zero logical screen dimensions. The recipient must open the crafted GIF for Viber to process it and abort with SIGABRT.

What is the impact of successful exploitation?

Successful exploitation crashes the Viber application, causing a denial of service. The provided data does not indicate confidentiality loss, integrity loss, or code execution.

CVE-2026-126546: Viber for iOS through 29.4.0.24 Denial of Service via Malformed GIF

Affected Software

Event History

Frequently Asked Questions

Who is affected by this issue?

What does an attacker need to do to trigger the crash?

What is the impact of successful exploitation?

Company

Resources

Contact

Frequently Asked Questions

Who is affected by this issue?

What does an attacker need to do to trigger the crash?

What is the impact of successful exploitation?