CVE-2026-42151 Prometheus Azure AD remote write OAuth client secret exposed via config API
Attackers with access to the config API can read exposed Azure AD OAuth client secrets due to improper redaction in Prometheus remote write configurations.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42151?
CVE-2026-42151 is a high-severity vulnerability in prometheus, published on 4 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Prometheus is an open-source monitoring system and time series database. Prior to versions 3.5.3 and 3.11.3, the client_secret field in the Azure AD remote write OAuth configuration (storage/remote/azuread) was typed as string instead of Secret. Prometheus redacts fields of type Secret when serving the configuration via the /-/config HTTP API endpoint. Because the field was a plain string, the Azure OAuth client secret was exposed in plaintext to any user or process with access to that endpoint. This issue has been patched in versions 3.5.3 and 3.11.3.
Which versions are affected by CVE-2026-42151?
4 open source packages ship an affected version, including github.com/prometheus/prometheus and prometheus. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/prometheus/prometheus Go | From 0.45.2 | 0.311.3 |
github.com/prometheus/prometheus Go | From 0.45.2 | 0.311.3 |
github.com/prometheus/prometheus Go | From 0.45.2 | 0.311.3 |
prometheus Bitnami | All versions | 0.305.3, 0.311.3, 3.5.3, 3.11.3 |
Linux distribution packages (1)
opentelemetry-collector-contrib Red Hat:hummingbird:1 | All versions | 0:0.153.0-1.hum1 |
Products include Prometheus Prometheus.
How do I fix CVE-2026-42151?
Upgrade github.com/prometheus/prometheus to 0.311.3 or later.
Is CVE-2026-42151 being exploited?
There is no known exploitation of CVE-2026-42151 in the wild and no public exploit code.
Other vulnerabilities in prometheus
- CVE-2026-42154 Prometheus: remote read endpoint allows denial of service via crafted snappy payload
- CVE-2021-29622 Arbitrary redirects under /new endpoint
- CVE-2019-3826 Cross-site scripting in prometheus
- CVE-2026-40179 Prometheus: Stored XSS via metric names and label values in web UI tooltips and metrics explorer
- CVE-2026-44903 Prometheus: Stored XSS via crafted histogram bucket label values in the heatmap display of the old Prometheus web UI
Sources
Also known as AZL-86610, BIT-prometheus-2026-42151, CLEANSTART-2026-BN60910, CLEANSTART-2026-CU14361, CLEANSTART-2026-IR38394, CLEANSTART-2026-KL35365 and 134 more.