CVE-2021-31317Network attack vector

Heap memory read via single-value dash reinterpretation

Published May 18, 2021 · Updated Aug 3, 2024

Type confusion in Telegram Android before 7.1.0 (2090), iOS before 7.1, and macOS before 7.1 allows remote attackers to read heap memory. The VDasher constructor reinterprets an attacker-controlled float array as paired Dash records, and updateActiveSegment reads a nonexistent gap when a sticker supplies one dash value. The victim must open the secret chat containing the sticker before Telegram renders it; ordinary chats filtered arbitrary stickers, and no memory write or code execution was demonstrated.

CVSS severity5.5
Medium
EPSS probability1.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Type confusion in Telegram Android before 7.1.0 (2090), iOS before 7.1, and macOS before 7.1 allows remote attackers to read heap memory. The VDasher constructor reinterprets an attacker-controlled float array as paired Dash records, and updateActiveSegment reads a nonexistent gap when a sticker supplies one dash value. The victim must open the secret chat containing the sticker before Telegram renders it; ordinary chats filtered arbitrary stickers, and no memory write or code execution was demonstrated.

The record

CVE
CVE-2021-31317
Published
May 18, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-843
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
4.3NVDAV:N/AC:M/Au:N/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-843Access of Resource Using Incompatible Type ('Type Confusion')

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo