Vulnerability · Published Oct 12, 2026 · Assigned by VulnCheck

CVE-2026-109427Telegram-Stremio 5.1.0 Broken Object Authorization via Stream IDs

Medium 6.5

In plain English

A medium-severity authorization bypass via user-controlled key in Telegram-Stremio from weebzone. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 11% of all known vulnerabilities).

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.2%top 88.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
weebzone	Telegram-Stremio	0 – through 5.1.0

Weakness: CWE-639, CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

References

Researcher Disclosure technical-description
VulnCheck Advisory: Telegram-Stremio 5.1.0 Broken Object Authorization via Stream IDs third-party-advisory