CVE-2026-49139 Nanobot < 0.2.1 SSRF via Microsoft Teams Channel serviceUrl Poisoning
Remote attackers can exfiltrate Bot Framework bearer tokens by poisoning Microsoft Teams serviceUrl values, leading to unauthorized data access.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-49139?
CVE-2026-49139 is a high-severity server-side request forgery vulnerability in HKUDS nanobot, published on 1 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-918
Which versions are affected by CVE-2026-49139?
How do I fix CVE-2026-49139?
No fix has been published for CVE-2026-49139 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-49139 being exploited?
There is no known exploitation of CVE-2026-49139 in the wild and no public exploit code.
Sources
Also known as GHSA-gv7x-pq3j-c5mj.