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Description

Nanobot prior to version 0.2.1 contains a server-side request forgery vulnerability in the Microsoft Teams channel handler that allows remote attackers to exfiltrate Bot Framework bearer tokens by supplying a forged activity with an attacker-controlled serviceUrl value. Attackers can poison the stored conversation reference by sending a crafted inbound activity to the Teams webhook, causing subsequent bot replies to transmit token-bearing Authorization header requests to an attacker-controlled host.

PUBLISHED Reserved 2026-05-27 | Published 2026-06-01 | Updated 2026-06-01 | Assigner VulnCheck




HIGH: 7.0CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:H/SI:H/SA:N

Problem types

Server-Side Request Forgery (SSRF)

Product status

Default status
affected

Any version before 0.2.1
affected

Credits

Chia Min Jun Lennon finder

References

github.com/HKUDS/nanobot/releases/tag/v0.2.1 release-notes

github.com/HKUDS/nanobot/pull/4047 issue-tracking

github.com/...ommit/232df45126bcf0f8fccd123d73714f202c8e8612 patch

www.vulncheck.com/...soft-teams-channel-serviceurl-poisoning third-party-advisory

cve.org (CVE-2026-49139)

nvd.nist.gov (CVE-2026-49139)

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