Bug 2499690 (CVE-2026-49478)

Summary: CVE-2026-49478 github.com/sigstore/fulcio: Fulcio: Server-Side Request Forgery and Kubernetes ServiceAccount token leakage
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: abarbaro, akoudelk, alizardo, anjoseph, anpicker, aprice, aruklets, cahl, cdrage, derez, dfreiber, dhanak, dkeler, doconnor, drosa, drow, dschmidt, dsimansk, dymurray, eborisov, ebourniv, eglynn, gbenhaim, gparvin, hasun, ibolton, jburrell, jcantril, jchui, jfula, jhe, jjoyce, jlanda, jmatthew, jmitchel, jmontleo, jowilson, jprabhak, jpretori, jsamir, jschluet, kaycoth, kbempah, kingland, kshier, ktsao, lball, lbragsta, lgallett, lgamliel, lhh, ljawale, manissin, mburns, mgarciac, mnovotny, msilmser, nboldt, ngough, niyer, nyancey, oaljalju, oezr, ometelka, pakotvan, pgaikwad, psrna, ptisnovs, rekumar, rhaigner, rhel-process-autobot, rjohnson, rojacob, rushinde, sakbas, sausingh, sbratsla, sbunciak, sdawley, simaishi, slucidi, solenoci, sseago, stcannon, sthirugn, suppawar, syedriko, teagle, thason, twaugh, tzivkovi, veshanka, vkumar, vvoronko, watson-tool-maintainers, wenshen, whayutin, wtam, xdharmai, yguenane
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in Fulcio's OpenID Connect (OIDC) Discovery client. This vulnerability allows a remote attacker to perform Server-Side Request Forgery (SSRF) by redirecting discovery requests to internal systems. Additionally, an attacker can manipulate the JSON Web Key Set (JWKS) Uniform Resource Identifier (URI) to poison the verifier cache with malicious keys, enabling the validation of attacker-controlled signatures. Furthermore, the flaw can lead to the leakage of Kubernetes ServiceAccount tokens to third-party hosts through cross-host redirects or misconfigured MetaIssuers, potentially exposing sensitive cluster credentials.
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-07-13 14:40:31 UTC
Three vulnerabilities in Fulcio's OIDC Discovery client: (1) Blind SSRF via cross-host redirects during discovery metadata fetch, (2) JWKS substitution and cache poisoning via manipulated jwks_uri pointing to attacker-controlled host, (3) Kubernetes ServiceAccount token leakage to third-party hosts via cross-host redirects or wildcard MetaIssuers. No workaround available. Fixed in Fulcio v1.8.6.