CVE-2021-31320 : What You Need to Know

Telegram Android <7.1.0 (2090), Telegram iOS <7.1, and Telegram macOS <7.1 are affected by a Heap Buffer Overflow vulnerability in the VGradientCache::generateGradientColorTable function of their rlottie library. This could allow a remote attacker to overwrite heap memory out-of-bounds on a victim device through a malicious animated sticker.

Understanding CVE-2021-31320

This CVE highlights a vulnerability in various Telegram versions that could be exploited by attackers to compromise user devices.

What is CVE-2021-31320?

CVE-2021-31320 is a Heap Buffer Overflow vulnerability found in Telegram for Android, iOS, and macOS. The flaw exists in the VGradientCache::generateGradientColorTable function of the rlottie library used in these Telegram versions.

The Impact of CVE-2021-31320

The vulnerability could be exploited by a remote attacker to tamper with heap memory beyond its allocated space on a targeted device. By sending a specially crafted animated sticker, the attacker could trigger the overflow, potentially leading to arbitrary code execution or a system crash.

Technical Details of CVE-2021-31320

This section provides further insight into the specific details of the vulnerability.

Vulnerability Description

The vulnerability arises from a Heap Buffer Overflow in the VGradientCache::generateGradientColorTable function of the rlottie library. Attackers could abuse this to manipulate heap memory on affected devices.

Affected Systems and Versions

Telegram Android versions earlier than 7.1.0 (2090), Telegram iOS versions prior to 7.1, and Telegram macOS versions below 7.1 are all impacted by this vulnerability.

Exploitation Mechanism

By sending a malicious animated sticker, a remote attacker could trigger the Heap Buffer Overflow, enabling them to disrupt the integrity of heap memory on the victim's device.

Mitigation and Prevention

To safeguard systems from the CVE-2021-31320 vulnerability, it is crucial to implement the following security measures.

Immediate Steps to Take

Users are advised to update their Telegram applications to versions that address the Heap Buffer Overflow vulnerability. Additionally, exercising caution when opening animated stickers from unknown sources can mitigate risks.

Long-Term Security Practices

It is recommended to regularly update software and applications to the latest versions to patch known vulnerabilities. Employing robust endpoint security solutions can also enhance overall protection against potential threats.

Patching and Updates

Telegram users should stay informed about security advisories from the Telegram team and promptly apply patches or updates released to address security vulnerabilities.