Telegram-Stremio: Insecure storage of Telegram session string
Summary
Telegram-Stremio through version 5.1.0 stores the operator's authenticated Telegram session string protected only by a keyless, reversible encoding instead of encryption. An attacker who can read the MongoDB database, a backup or logs can decode the value and obtain a fully authenticated Telegram session. This gives full control of the operator's Telegram account, even if two-step verification is enabled.
Affected
- Telegram-Stremio 0 to and including 5.1.0
- Default configuration: unaffected versions according to the CNA record
Fixed in
Unknown.
Workaround
- Restrict access to the MongoDB database to the local network and enable authentication.
- Treat backups and logs that may contain the database as sensitive and encrypt them.
- Revoke the stored Telegram session in Telegram's active-sessions list and remove it from the service where possible.
- Re-authenticate only after a fixed version has been confirmed.
Exploitation
- Not known to be exploited; not listed in the CISA KEV catalogue.
- CISA SSVC: exploitation none, automatable yes, technical impact partial.
- EPSS score 0.0011.
- No public exploit identified.
Our recommendation
- Check whether Telegram-Stremio is in use, for example in Docker or home-lab setups.
- If it is in use, restrict database and backup access now and revoke the stored Telegram session.
- Use a dedicated Telegram account with limited value for the service.
- Treat the issue as open until the vendor publishes a patched version and a changelog entry.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Researcher write-up (gist) gist.github.com
- VulnCheck advisory www.vulncheck.com
- OpenCVE entry CVE-2026-109426 app.opencve.io
- Vulners RAPID7 entry CVE-2026-109426 vulners.com
- Telegram-Stremio repository github.com
- Telegram-Stremio releases github.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 16:37.
Original description (NVD)
Telegram-Stremio through 5.1.0 contains an insecure storage vulnerability that allows attackers with access to the MongoDB database, backups, or logs to recover the operator's authenticated Telegram session string, which is protected only by a keyless, reversible encoding transform rather than actual encryption. Attackers can round-trip the stored value through the repository's own decode_string function with no secret key to obtain a fully authenticated Telegram session, granting complete control of the operator's Telegram account even when two-step verification is enabled.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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