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.
https://www.vulncheck.com/advisories/nanobot-ssrf-via-microsoft-teams-channel-serviceurl-poisoning
https://github.com/HKUDS/nanobot/releases/tag/v0.2.1
https://github.com/HKUDS/nanobot/pull/4047
https://github.com/HKUDS/nanobot/commit/232df45126bcf0f8fccd123d73714f202c8e8612
Published: 2026-06-01
Updated: 2026-06-02
Base Score: 6.4
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N
Severity: Medium
Base Score: 9.1
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Severity: Critical
Base Score: 7
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:H/SI:H/SA:N
Severity: High
EPSS: 0.00132