CVE-2026-49478

HIGHPre-NVD 8.78.7
EchelonGraph scoreLOW confidence

This high-severity CVE scores 8.7 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cna:github_m
8.7
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: —CVSS: 8.7Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Fulcio has OIDC Discovery Redirect Following Allows SSRF and JWKS Substitution for Meta-Issuer Paths, with Kubernetes Service-Account Token Leakage

Impact

Three security vulnerabilities were identified in the OIDC Discovery client:

  • Blind Server-Side Request Forgery (SSRF) via Cross-Host Redirects:
Fulcio uses an HTTP client to fetch OIDC discovery metadata (/.well-known/openid-configuration). Prior to this fix, if a configured issuer returned an HTTP redirect to a different host, the client followed it by default. This allowed a compromised or malicious issuer to redirect Fulcio's discovery requests to internal-only systems, resulting in blind SSRF.
  • JWKS Substitution and Cache Poisoning:
Because cross-host redirects were permitted during OIDC discovery, an attacker could manipulate the discovery flow to return a malicious jwks_uri pointing to an attacker-controlled host. When Fulcio successfully initialized the provider and cached the resulting verifier in the verifier cache, it poisoned the cache with the attacker's verification keys. The attacker could then present signatures validated against the poisoned keys.
  • Kubernetes ServiceAccount Token Leakage:
Fulcio mounts an in-cluster Kubernetes ServiceAccount token to authenticate OIDC discovery requests sent to the local control plane API server (https://kubernetes.default.svc). * Cross-Host Redirects & JWKS: The token was previously attached globally by the transport, leaking it to third-party hosts if the issuer performed a redirect or if the jwks_uri pointed to a different domain. * Wildcard MetaIssuers: If a wildcard MetaIssuer of type kubernetes (e.g., matching external EKS/GKE endpoints) was matched, and a local Kubernetes issuer was present in the config, the transport loaded and attached the local in-cluster ServiceAccount token to outbound requests sent to the external host.

Patches

The following mitigations have been applied:

* Blocked Cross-Host Redirects: A custom callback is configured on all OIDC discovery HTTP clients to reject redirects that attempt to cross the original issuer's host boundary. * Restricted Token Injection: Updated the transport to only attach the ServiceAccount token when the outgoing request's host exactly matches the configured host of the issuer. * Restricted Local Token Loading: Constrained the loader to only load and wrap the transport with the local ServiceAccount token when the target issuer URL exactly matches the private local API server (https://kubernetes.default.svc).

Workarounds

None, upgrade to v1.8.6

CVSS v3
8.7
EG Score
8.7(low)
EPSS
—
KEV
Not listed

Published

June 30, 2026

Last Modified

June 30, 2026

Vendor Advisories for CVE-2026-49478(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 13× in last 7d / 13× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-07 04:08 UTCEG score recompute
  2. 2026-07-06 15:25 UTCEG score recompute
  3. 2026-07-06 02:40 UTCEG score recompute
  4. 2026-07-05 13:57 UTCEG score recompute
  5. 2026-07-05 01:14 UTCEG score recompute
  6. 2026-07-04 12:30 UTCEG score recompute
  7. 2026-07-03 23:48 UTCEG score recompute
  8. 2026-07-03 11:06 UTCEG score recompute
  9. 2026-07-02 22:19 UTCEG score recompute
  10. 2026-07-02 09:37 UTCEG score recompute
  11. 2026-07-01 20:55 UTCEG score recompute
  12. 2026-07-01 08:13 UTCEG score recompute
  13. 2026-06-30 19:31 UTCEG score recompute

Frequently asked(4)

What is CVE-2026-49478?
CVE-2026-49478 is a high vulnerability published on June 30, 2026. Fulcio has OIDC Discovery Redirect Following Allows SSRF and JWKS Substitution for Meta-Issuer Paths, with Kubernetes Service-Account Token Leakage Impact Three security vulnerabilities were identified in the OIDC Discovery client: 1. Blind Server-Side Request Forgery (SSRF) via Cross-Host…
When was CVE-2026-49478 disclosed?
CVE-2026-49478 was first published in the National Vulnerability Database on June 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-49478?
CVE-2026-49478 has a CVSS v4.0 base score of 8.7 (CNA self-assessment; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-49478?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49478, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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