CVE-2021-31321 Explained : Impact and Mitigation

Telegram Android versions prior to 7.1.0 (2090), Telegram iOS versions prior to 7.1, and Telegram macOS versions prior to 7.1 are susceptible to a Stack-Based Overflow vulnerability in the gray_split_cubic function of the custom rlottie library. This flaw could allow a remote attacker to overwrite Telegram's stack memory on a target device using a malicious animated sticker.

Understanding CVE-2021-31321

This CVE highlights a critical security issue in Telegram's implementation affecting multiple platforms.

What is CVE-2021-31321?

The vulnerability lies in the handling of animated stickers within Telegram clients, allowing an attacker to manipulate stack memory through a crafted sticker.

The Impact of CVE-2021-31321

Exploitation of this vulnerability could lead to unauthorized access to sensitive information or the execution of arbitrary code on the target device.

Technical Details of CVE-2021-31321

This section dives deeper into the technical aspects of the CVE.

Vulnerability Description

The vulnerability arises from a stack-based overflow in the gray_split_cubic function of the rlottie library used by Telegram.

Affected Systems and Versions

Telegram Android versions prior to 7.1.0 (2090), Telegram iOS versions prior to 7.1, and Telegram macOS versions prior to 7.1 are impacted.

Exploitation Mechanism

By sending a specially crafted animated sticker, a remote attacker can trigger the overflow and potentially execute malicious actions.

Mitigation and Prevention

It is crucial to take immediate steps to address this CVE and implement long-term security measures.

Immediate Steps to Take

Users should update their Telegram apps to the latest versions where the vulnerability has been patched.

Long-Term Security Practices

Regularly update software, be cautious of opening files from unknown sources, and consider using security tools to monitor for suspicious activities.

Patching and Updates

Telegram has released updates addressing this vulnerability; users are strongly advised to install these updates promptly to safeguard their devices.