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CVE-2026-49478— Fulcio has OIDC Discovery Redirect Following Allows SSRF and JWKS Substitution for Meta-Issuer Paths, with Kubernetes Service-Account Token Leakage

Quick assessment

Affected
sigstore fulcio
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

sigstore fulcio是sigstore组织的一个代码签名证书颁发服务。 sigstore fulcio 1.8.5及之前版本存在服务端请求伪造漏洞，该漏洞源于在OIDC发现过程中不正确地跟随跨主机重定向并附加Kubernetes ServiceAccount令牌，可能导致恶意或受入侵的签发者执行盲SSRF、替换和缓存恶意JWKS密钥或向外部主机泄露ServiceAccount令牌。

CVSS 8.7 · High EPSS 0.28% · P19

Affected Version Matrix 1

VendorProduct Version RangeStatus
sigstore fulcio < 1.8.6 affected
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I. Basic Information for CVE-2026-49478

Vulnerability Information
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Vulnerability Title
Fulcio has OIDC Discovery Redirect Following Allows SSRF and JWKS Substitution for Meta-Issuer Paths, with Kubernetes Service-Account Token Leakage
Source: CVE Program / CVE List V5
Vulnerability Description
Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Versions through 1.8.5 improperly follow cross-host redirects and attach Kubernetes ServiceAccount tokens during OIDC discovery, allowing a malicious or compromised issuer to perform blind SSRF, substitute and cache malicious JWKS keys, or disclose ServiceAccount tokens to external hosts. Version 1.8.6 blocks cross-host redirects, restricts token injection, and restricts local token loading. No known workarounds are available.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
服务端请求伪造(SSRF)
Source: CVE Program / CVE List V5
Vulnerability Title
sigstore fulcio 服务端请求伪造漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
sigstore fulcio是sigstore组织的一个代码签名证书颁发服务。 sigstore fulcio 1.8.5及之前版本存在服务端请求伪造漏洞，该漏洞源于在OIDC发现过程中不正确地跟随跨主机重定向并附加Kubernetes ServiceAccount令牌，可能导致恶意或受入侵的签发者执行盲SSRF、替换和缓存恶意JWKS密钥或向外部主机泄露ServiceAccount令牌。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
sigstore fulcio < 1.8.6 -

II. Public POCs for CVE-2026-49478

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 8187 chars
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Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
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III. Intelligence Information for CVE-2026-49478

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Patches & Fixes for CVE-2026-49478 (2)

Vendor Advisories for CVE-2026-49478 (1)

Vendor Pages for CVE-2026-49478 (1)

IV. Related Vulnerabilities

Same product: fulcio
Same vendor: sigstore
Same weakness: CWE-918

V. Comments for CVE-2026-49478

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