CVE-2021-31318

Heap memory disclosure via unchecked rlottie static cast

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. LOTCompLayerItem statically casts an object of an unverified type to LOTLayerData, then accesses fields beyond the actual object's bounds. A victim must process a malicious animated sticker, and the documented consequence is limited to an out-of-bounds heap read.

CVSS severity5.5
Medium
EPSS probability1.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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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. LOTCompLayerItem statically casts an object of an unverified type to LOTLayerData, then accesses fields beyond the actual object's bounds. A victim must process a malicious animated sticker, and the documented consequence is limited to an out-of-bounds heap read.

The record

CVE
CVE-2021-31318
Published
May 18, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-843, T1203
Attack vector
local
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

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-843Access of Resource Using Incompatible Type ('Type Confusion')
T1203Exploitation for Client Execution

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

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Your stack

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