# CVE-2025-66506: golang-github-sigstore-fulcio: Fulcio is a free-to-use certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) iden...

CVE-2025-66506 is fixed in 9 products on 1 platform, first by DEBIAN-CVE-2025-66506, released December 4, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-66506
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0023
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 4, 2025

## Description

Fulcio is a free-to-use certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.3, function identity.extractIssuerURL splits (via a call to strings.Split) its argument (which is untrusted data) on periods. As a result, in the face of a malicious request with an (invalid) OIDC identity token in the payload containing many period characters, a call to extractIssuerURL incurs allocations to the tune of O(n) bytes (where n stands for the length of the function's argument), with a constant factor of about 16. This vulnerability is fixed in 1.8.3.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | golang-github-sigstore-fulcio Debian 14 | 1.8.5-1 | [DEBIAN-CVE-2025-66506](https://patchblox.com/security/data/fix/linux/debian-cve-2025-66506.md) | Dec 4, 2025 |
| Linux | govulncheck-vulndb opensuse-leap 15.6 | 0.0.20251209T172047-150000.1.127.1 | [SUSE-SU-2025:4395-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4395-1.md) | Dec 15, 2025 |
| Linux | govulncheck-vulndb opensuse-leap 16.0 | 0.0.20260723T184607-160000.1.1 | [OPENSUSE-SU-2026:21483-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21483-1.md) | Jul 30, 2026 |
| Linux | govulncheck-vulndb sles 15.6 | 0.0.20251209T172047-150000.1.127.1 | [SUSE-SU-2025:4395-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4395-1.md) | Dec 15, 2025 |
| Linux | podman-tui Fedora 43 | 1.11.3-1.fc43 | [FEDORA-2026-1842AAEA5D](https://patchblox.com/security/data/fix/linux/fedora-2026-1842aaea5d.md) | Jun 28, 2026 |
| Linux | podman-tui-debuginfo Fedora 43 | 1.11.3-1.fc43 | [FEDORA-2026-1842AAEA5D](https://patchblox.com/security/data/fix/linux/fedora-2026-1842aaea5d.md) | Jun 28, 2026 |
| Linux | podman-tui-debugsource Fedora 43 | 1.11.3-1.fc43 | [FEDORA-2026-1842AAEA5D](https://patchblox.com/security/data/fix/linux/fedora-2026-1842aaea5d.md) | Jun 28, 2026 |
| Linux | prometheus-podman-exporter Fedora 43 | 1.21.2-1.fc43 | [FEDORA-2026-A96D4EE174](https://patchblox.com/security/data/fix/linux/fedora-2026-a96d4ee174.md) | Jun 28, 2026 |
| Linux | prometheus-podman-exporter-debuginfo Fedora 43 | 1.21.2-1.fc43 | [FEDORA-2026-A96D4EE174](https://patchblox.com/security/data/fix/linux/fedora-2026-a96d4ee174.md) | Jun 28, 2026 |
| Linux | prometheus-podman-exporter-debugsource Fedora 43 | 1.21.2-1.fc43 | [FEDORA-2026-A96D4EE174](https://patchblox.com/security/data/fix/linux/fedora-2026-a96d4ee174.md) | Jun 28, 2026 |
| Linux | runfinch-finch amzn 2023 | 1.10.0-1.amzn2023.0.6 | [ALAS2023-2025-1336](https://patchblox.com/security/data/fix/linux/alas2023-2025-1336.md) | Jan 7, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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