Security readout for executives and security teams
Plain-English summary
Older Telegram clients could mishandle a malicious animated sticker and read stack memory outside intended bounds. The issue affects Telegram Android before 7.1.0 build 2090, iOS before 7.1, and macOS before 7.1. No source provided confirms active exploitation.
Executive priority
Treat this as a targeted endpoint hygiene issue. Prioritize managed devices, executives, and teams using Telegram for business communication, but do not represent it as actively exploited from the provided evidence.
Technical view
CVE-2021-31315 is a stack-based overflow in Telegram's custom rlottie fork, specifically the blit function used for animated stickers. A remote attacker might trigger out-of-bounds stack memory access through a crafted animated sticker. Public data does not provide CVSS, CWE, or confirmed code execution impact.
Likely exposure
Exposure is limited to endpoints running affected Telegram client versions: Android below 7.1.0 build 2090, iOS below 7.1, or macOS below 7.1.
Exploitation context
The reported vector is remote delivery of a malicious animated sticker. The available sources say an attacker might access stack memory out-of-bounds, but do not confirm weaponized exploitation or inclusion in CISA KEV.
Researcher notes
The source bundle identifies the vulnerable component and vector, but omits CVSS, CWE, detailed impact, and exploit maturity. Validation should focus on client version exposure, not assumptions about upstream rlottie or unrelated Telegram platforms.
Mitigation direction
- Update Telegram Android to 7.1.0 build 2090 or later.
- Update Telegram iOS and macOS to 7.1 or later.
- Use MDM or endpoint inventory to remove outdated Telegram clients.
- Check Telegram or vendor guidance for any platform-specific remediation notes.
Validation and detection
- Inventory Telegram versions across Android, iOS, and macOS endpoints.
- Flag Android builds below 7.1.0 build 2090.
- Flag iOS and macOS clients below version 7.1.
- Review mobile security telemetry for suspicious sticker-related crashes if available.
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-2021-31315 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/advisories/telegram-rlottie-blit-stack-buffer-overflow/CVE reference · x_refsource_MISC
- https://www.shielder.it/blog/2021/02/hunting-for-bugs-in-telegrams-animated-stickers-remote-attack-surface/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.