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TI-2026-71285 Aliases CVE-2026-109427GHSA-q45w-888c-vpfr

Broken object authorization in Telegram-Stremio exposes private chats

Priority LOW 31CWE-639Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
High · None · None
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-639.

Summary

Telegram-Stremio through 5.1.0 contains a broken object-level authorization flaw (CWE-639) that lets an authenticated token holder read arbitrary chat messages by forging unsigned stream IDs decoded by encode_string and decode_string. An attacker who can enumerate sequential msg_id values and set a global flag in the stream_handler endpoint can route requests through the operator's personal Userbot account, exposing private channels, groups and Saved Messages. The unauthenticated thumb_handler endpoint also discloses thumbnails from the same chats without token validation.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

Telegram-Stremio through 5.1.0 contains a broken object-level authorization vulnerability that allows authenticated token holders to access arbitrary chat messages by forging unsigned, unauthenticated stream IDs decoded via encode_string/decode_string functions. Attackers can craft or enumerate sequential msg_id values and set a global flag in the stream_handler endpoint to route requests through the operator's personal Userbot account, exposing private channels, groups, and Saved Messages, while the unauthenticated thumb_handler endpoint further discloses thumbnails from those same chats without any token validation.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00209 11th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
weebzoneTelegram-Stremioup to 5.1.0—No fix listedCNA
  • Telegram-Stremio Vendorweebzone Affected up to 5.1.0 Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for Telegram-Stremio.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Timeline

  1. 2026-10-12 Threatist record created from CVE-2026-109427
  2. 2026-10-13 Alias added: GHSA-q45w-888c-vpfr
  3. 2026-10-13 Priority changed: MEDIUM → LOW
  4. 2026-10-26 CISA SSVC decision points changed

References

Other 1

  • TI-2026-71284 Telegram-Stremio leaks reversible Telegram session strings CVSS 4.0HIGH 8.2

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences