CVE-2026-12566 SSRF via unvalidated WWW-Authenticate realm in docker_pull module
A man-in-the-middle attacker can redirect authentication requests to arbitrary endpoints via unvalidated realm headers, potentially leaking tokens.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-12566?
CVE-2026-12566 is a low-severity server-side request forgery vulnerability in Black Lantern Security BBOT, published on 17 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
The docker_pull module uses the realm parameter from a Docker registry's WWW-Authenticate response header as the authentication endpoint without validation. An attacker in a man-in-the-middle position between bbot and a Docker registry could modify this header to redirect the authentication request to an arbitrary endpoint, potentially leaking authentication tokens.
Weakness: CWE-918
Which versions are affected by CVE-2026-12566?
3 open source packages ship an affected version, including bbot.
| Package | Affected | Fixed in |
|---|---|---|
bbot PyPI | From 2.0.0 | 2.8.5 |
bbot PyPI | From 2.0.0 | 2.8.5 |
bbot PyPI | From 2.0.0 | 2.8.5 |
How do I fix CVE-2026-12566?
Upgrade bbot to 2.8.5 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-12566 being exploited?
There is no known exploitation of CVE-2026-12566 in the wild and no public exploit code.
Sources
Also known as GHSA-3mp7-vp6j-2mxx, PYSEC-2026-2391.