Security readout for executives and security teams
Plain-English summary
Older Telegram clients could mishandle a malicious animated sticker and read memory outside expected bounds. The business risk is mainly to users still running Telegram Android before 7.1.0 build 2090, iOS before 7.1, or macOS before 7.1.
Executive priority
Treat as a targeted endpoint hygiene issue, not an enterprise-wide emergency, unless Telegram is widely used in the organization or cannot be version-controlled.
Technical view
The issue is a heap buffer overflow in LottieParserImpl::parseDashProperty within Telegram's custom rlottie fork. The reachable surface is animated sticker parsing. The provided CVE data does not include CVSS, CWE, confirmed exploitation, or detailed vendor remediation text.
Likely exposure
Exposure is limited to endpoints using affected Telegram client versions. Organizations with unmanaged mobile or macOS Telegram installations have the most plausible residual exposure.
Exploitation context
The sources describe a remote attacker using a malicious animated sticker. CISA KEV is false, and the provided sources do not support claims of active exploitation.
Researcher notes
Evidence points to a parser memory-safety flaw in Telegram's rlottie fork. Public data provided here is thin: no CVSS, CWE, proof of exploitation, or full impact beyond out-of-bounds heap access is supplied.
Mitigation direction
- Inventory Telegram Android, iOS, and macOS client versions.
- Remove or upgrade clients below the listed 7.1 thresholds.
- Check Telegram vendor guidance for supported fixed versions.
- Restrict unapproved Telegram use on managed endpoints.
- Monitor mobile and macOS fleet compliance for outdated clients.
Validation and detection
- Confirm no managed device runs Telegram Android before 7.1.0 build 2090.
- Confirm no managed iOS or macOS device runs Telegram before 7.1.
- Review MDM or endpoint inventory for unmanaged Telegram installs.
- Document compensating controls where client version cannot be verified.
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-2021-31323 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-lottieparserimpl-parsedashproperty-heap-buffer-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.