---
title: "CVE-2026-49478\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2026-49478?format=md
keywords: index, follow
---

# CVE-2026-49478

Publication date 13 August 2026

Last updated 19 August 2026

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**8.7 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2026-49478?format=md#impact-score)

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## 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.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| golang-github-sigstore-fulcio | 26.04 LTS resolute | Needs evaluation |
| 24.04 LTS noble | Not in release |
| 22.04 LTS jammy | Not in release |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

8.7 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | High |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Changed |
  | Confidentiality impact | High |
  | Integrity impact | High |
  | Availability impact | None |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 8.7 · High |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-49478)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-49478)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-49478)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-49478)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-49478>
* <https://github.com/sigstore/fulcio/pull/2354>