Security readout for executives and security teams
Plain-English summary
This issue affects older Telegram apps. A malicious animated sticker could trigger an integer overflow in Telegram’s rlottie-based animation handling, potentially reading or accessing heap memory outside normal bounds on a victim device.
Executive priority
Prioritize remediation where Telegram is installed on executive, admin, or sensitive business devices. Business risk is lower if Telegram is absent or fully updated, but evidence is incomplete because severity and exploitation status are not established in the bundle.
Technical view
CVE-2021-31319 is an integer overflow in LOTGradient::populate in Telegram’s custom fork of rlottie. Affected versions are Telegram Android before 7.1.0 (2090), iOS before 7.1, and macOS before 7.1. The described vector is a malicious animated sticker.
Likely exposure
Exposure is limited to devices running the listed pre-7.1 Telegram versions and able to receive or render malicious animated stickers. Current exposure depends on app inventory, update posture, and whether Telegram is present on managed endpoints.
Exploitation context
The provided sources describe a remote attack surface through animated stickers, but the bundle provides no CVSS score, no CISA KEV listing, and no cited evidence of active exploitation.
Researcher notes
The key research angle is Telegram’s animated sticker parser and its custom rlottie fork, specifically LOTGradient::populate. The source bundle supports possible heap out-of-bounds memory access, but not confirmed code execution, exploit availability, or active attacks.
Mitigation direction
- Upgrade Telegram Android, iOS, and macOS clients beyond the affected versions.
- Use MDM or endpoint inventory to enforce minimum Telegram app versions.
- Check Telegram or advisory guidance for any additional vendor-recommended actions.
- Remove unsupported or unmanaged Telegram installations from sensitive environments.
Validation and detection
- Inventory Telegram installations across managed Android, iOS, and macOS devices.
- Confirm Android versions are at least 7.1.0 build 2090.
- Confirm iOS and macOS versions are at least 7.1.
- Document whether Telegram use is business-required on sensitive endpoints.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-31319 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.shielder.it/blog/2021/02/hunting-for-bugs-in-telegrams-animated-stickers-remote-attack-surface/CVE reference · x_refsource_MISC
- https://www.shielder.it/advisories/telegram-rlottie-lotgradient-populate-integer-overflow/CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.