CVE-2026-119566

Description

Prometheus through 3.15.1 contains a credential leak vulnerability that allows attackers to capture Azure AD or Google IAM bearer tokens by redirecting remote_write requests to another host. Attackers controlling the remote-write endpoint or a redirecting server can return a 3xx to their host and replay the token, for example to write metrics to the victim's backend.

References

• https://abraxaslabs.tech/research/prometheus-bearer-redirect
• https://github.com/prometheus/common/pull/901
• https://github.com/prometheus/prometheus
• https://github.com/prometheus/prometheus/blob/v3.15.1/storage/remote/azuread/azuread.go#L326-L333
• https://github.com/prometheus/prometheus/blob/v3.15.1/storage/remote/client.go#L205-L216