CVE-2026-49478: Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity

Q: How do I fix CVE-2026-49478?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Q: Is CVE-2026-49478 being exploited?

CVE-2026-49478 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-49478 affect?

CVE-2026-49478 affects affected software. Severity is high (CVSS 8.7). 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,

Q: How urgent is CVE-2026-49478?

Priority 40/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 8.7REMOTE

CVE-2026-49478 is a high-severity flaw (CVSS 8.7) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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, restri

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	8.7 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 80%)
CISA exploited list	No
Weakness	CWE-918
Published	2026-08-13
Last modified	2026-10-23

Publisher (CNA): GitHub, Inc.

Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-08-13 13:19 UTCPublished CVE record published
2026-10-23 18:10 UTCUpdated Record last modified

Exact fixes by distribution

Go · github.com/sigstore/fulcio · FIXED · 1.8.6 · vulnerable: <= 1.8.5 · source

go get github.com/sigstore/fulcio@v1.8.6 go list -m github.com/sigstore/fulcio

Fedora ELN · ntpd-rs · FIXED · 1.7.2-3.eln159 · FEDORA-2026-57e4a99310 · source

sudo dnf upgrade --advisory=FEDORA-2026-57e4a99310

Fedora 46 · moby-engine · FIXED · 29.9.2-2.fc46 · FEDORA-2026-4856be87b3 · source

sudo dnf upgrade --advisory=FEDORA-2026-4856be87b3

Debian 13 · golang-github-sigstore-fulcio · NO FIX YET

RHEL 10 · buildah · DEFERRED

RHEL 10 · podman · DEFERRED

RHEL 10 · rhel10/bootc-image-builder · DEFERRED

RHEL 10 · rhel10-eus/rhel-10.0-bootc · DEFERRED

RHEL 10 · rhel10-eus/rhel-10.0-bootc-image-builder · DEFERRED

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-2023 · source

sudo dnf update --advisory=ALAS2023-2026-2023

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-49478?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-49478 being exploited?

CVE-2026-49478 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-49478 affect?

CVE-2026-49478 affects affected software. Severity is high (CVSS 8.7). 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,

How urgent is CVE-2026-49478?

Priority 40/100. High severity; Remotely exploitable, no login, no user action

Software pages

Kubernetes vulnerabilities

References

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