# CVE-2026-119566: Prometheus through 3.15.1 Credential Leak via remote_write Cross-Host Redirects

Status: published. Published: 2026-10-30. Updated: 2026-11-04.

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.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/prometheus/common/pull/901

## Affected products and versions

- prometheus / prometheus (prometheus/prometheus): ≥ 0; ≤ 3.15.1 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.3 (medium); CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 4.8 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N; source: CNA: VulnCheck

- CVSS 4.0: 6.3 (medium); CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 4.8 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.20% as of 2026-11-04; percentile 10.08%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-522

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/prometheus/prometheus/blob/v3.15.1/storage/remote/azuread/azuread.go#L326-L333 (CNA: VulnCheck; technical-description)

- https://github.com/prometheus/prometheus/blob/v3.15.1/storage/remote/client.go#L205-L216 (CNA: VulnCheck; technical-description)

- https://github.com/prometheus/common/pull/901 (CNA: VulnCheck; related, patch, issue-tracking)

- https://abraxaslabs.tech/research/prometheus-bearer-redirect (CNA: VulnCheck; third-party-advisory)

- https://github.com/prometheus/prometheus (CNA: VulnCheck; product)

- https://www.vulncheck.com/advisories/prometheus-through-3.15.1-credential-leak-via-remote-write-cross-host-redirects (CNA: VulnCheck; third-party-advisory)

- https://abraxaslabs.tech/research/prometheus-bearer-redirect (disclosure@vulncheck.com)

- https://github.com/prometheus/common/pull/901 (disclosure@vulncheck.com)

- https://github.com/prometheus/prometheus (disclosure@vulncheck.com)

- https://github.com/prometheus/prometheus/blob/v3.15.1/storage/remote/azuread/azuread.go#L326-L333 (disclosure@vulncheck.com)

- https://github.com/prometheus/prometheus/blob/v3.15.1/storage/remote/client.go#L205-L216 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/prometheus-through-3.15.1-credential-leak-via-remote-write-cross-host-redirects (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-119566; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-119566; retrieved 2026-11-05; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-119566; retrieved 2026-11-04; source updated Not reported

Revision: e51f483cd89fd9cdbfe1045049343a533d1ea1a13655c0f5d1e997a29cbd9e87

Canonical: https://y2.dev/cve/CVE-2026-119566

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.