Skip to main content

Fulcio CVE-2026-22772

MEDIUM
Server-Side Request Forgery (SSRF) (CWE-918)
2026-01-12 security-advisories@github.com GHSA-59jp-pj84-45mr
SSRF Red Hat Fulcio Suse Linuxfoundation
5.8
CVSS 3.1 · GitHub Advisory
View

Vulnerability Assessment

Weakness
CWE
CWE-918
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V4 - API and Web Service URL allowlisting, SSRF prevention
MITRE ATT&CK

2 techniques across 2 tactics: Initial Access, Credential Access

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Sign in to read
Impact

CVSS 5.8 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitable via remote/network. Public exploit/POC available.
Exploit ScenarioDerived

A remote attacker could exploit this vulnerability to compromise the affected system.
This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.0% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv1 – Mar 12, 2026

Fulcio versions prior to 1.8.5 allow unauthenticated attackers to bypass MetaIssuer URL validation through unanchored regex patterns, enabling blind SSRF attacks against internal services. Although the vulnerability is limited to read-only GET requests with no response exfiltration, attackers can probe internal networks to discover active services and infrastructure. Public exploit code exists for this medium-severity issue, and a patch is available in version 1.8.5.

Earlier versions of this analysis (1)
v1 Mar 12, 2026 - 21:54 CVSS 5.8

Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.5, Fulcio's metaRegex() function uses unanchored regex, allowing attackers to bypass MetaIssuer URL validation and trigger SSRF to arbitrary internal services. [CVSS 5.8 MEDIUM]

RemediationAI

A vendor patch is available — apply it immediately. Fixed in version 1.8.5.. Restrict network access to the affected service where possible.

Affected Packages

go github.com/sigstore/fulcio fix: 1.8.5

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in go

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Sign in to check
Technical ContextAI · show details

Classified as CWE-918 (Server-Side Request Forgery (SSRF)). Affects Fulcio. Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.5, Fulcio's metaRegex() function uses unanchored regex, allowing attackers to bypass MetaIssuer URL validation and trigger SSRF to arbitrary internal services. Since the SSRF only can trigger GET requests, the request cannot mutate state. The response from the GET request is not returned to the caller so data exfiltration is not possible. A malicious actor could attempt to

Know when Fulcio gets its next vulnerability

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources
Continue with Google Continue with GitHub

No credit card · 7-day full trial

Severity by source

GitHub Advisory PRIMARY 5.8 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
SUSE MEDIUM
Red Hat 5.8 MEDIUM

Primary rating from GitHub Advisory.

CVSS VectorGitHub Advisory

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
None
Availability
None

Lifecycle Timeline

3
PoC Detected
Mar 05, 2026 - 13:48 vuln.today
Public exploit code
Patch released
Mar 05, 2026 - 13:48 nvd
Patch available
CVE Published
Jan 12, 2026 - 21:15 nvd
MEDIUM 5.8

DescriptionGitHub Advisory

Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.5, Fulcio's metaRegex() function uses unanchored regex, allowing attackers to bypass MetaIssuer URL validation and trigger SSRF to arbitrary internal services. Since the SSRF only can trigger GET requests, the request cannot mutate state. The response from the GET request is not returned to the caller so data exfiltration is not possible. A malicious actor could attempt to probe an internal network through Blind SSRF. This vulnerability is fixed in 1.8.5.

Executive ViewAI

Why It Matters

Organizations using Fulcio should be aware of moderate risk from CVE-2026-22772, a server-side request forgery vulnerability rated CVSS 5.8. Users could be tricked into performing unintended actions. Proof-of-concept code is publicly available. A patch is available and should be applied during regular vulnerability management.

Business Impact: Low
Compensating Controls

Apply vendor patch. If patching is delayed: implement egress filtering, block metadata endpoints.

Threat Intelligence Overview

EPSS Score
0.0%
Top 98% exploitable
Exploit
POC
Public exploit code exists
Data Quality
4 sources
Confidence: Medium
NVD CVE.org EPSS Vendor GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC Yes
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact
Low

Priority Score

49
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +29
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Server-Side Request Forgery HIGH

Server-Side Request Forgery exploits applications that fetch remote resources based on user-supplied URLs.

Affected Products (CPE)GitHub Advisory

cpe:2.3:a:linuxfoundation:fulcio:*:*:*:*:*:*:*:*

More in Fulcio

View all
CVE-2025-66506 HIGH
7.5 Dec 04

A security vulnerability in Fulcio (CVSS 7.5). High severity vulnerability requiring prompt remediation. Vendor patch is

Same weakness CWE-918 – Server-Side Request Forgery (SSRF)

View all
CVE-2021-34473 CRITICAL POC
9.1
CVE-2021-26855 CRITICAL POC
9.1
CVE-2021-21985 CRITICAL POC
9.8
CVE-2022-41040 HIGH POC
8.8
CVE-2024-21893 HIGH POC
8.2
CVE-2021-40438 CRITICAL POC
9.0
CVE-2021-22054 HIGH POC
7.5
CVE-2021-21975 HIGH POC
7.5

Same technique SSRF

View all
CVE-2016-3718 MEDIUM POC
5.5

Vendor StatusVendor

SUSE

Severity: Medium
Product Status
Image SL-Micro Image SL-Micro-Azure Image SL-Micro-BYOS-Azure Image SL-Micro-BYOS-EC2 Image SL-Micro-BYOS-GCE Image SL-Micro-Base-qcow Image SL-Micro-Default Image SL-Micro-Default-SelfInstall Image SL-Micro-Default-encrypted Image SL-Micro-Default-qcow Image SL-Micro-EC2 Image SLE-Micro Image SLE-Micro-Azure Image SLE-Micro-BYOS Image SLE-Micro-BYOS-Azure Image SLE-Micro-BYOS-EC2 Image SLE-Micro-BYOS-GCE Image SLE-Micro-EC2 Image SLE-Micro-GCE Image SUSE-Multi-Linux-Manager-Proxy-BYOS-Azure Image SUSE-Multi-Linux-Manager-Proxy-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Proxy-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-Azure-llc Image SUSE-Multi-Linux-Manager-Server-Azure-ltd Image SUSE-Multi-Linux-Manager-Server-BYOS-Azure Image SUSE-Multi-Linux-Manager-Server-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Server-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-EC2-llc Image SUSE-Multi-Linux-Manager-Server-EC2-ltd Affected
SUSE Linux Enterprise Desktop 15 SP7 SUSE Linux Enterprise High Performance Computing 15 SP7 SUSE Linux Enterprise Module for Basesystem 15 SP7 SUSE Linux Enterprise Server 15 SP7 SUSE Linux Enterprise Server for SAP Applications 15 SP7 Fixed
SUSE Linux Enterprise Server 16.0 SUSE Linux Enterprise Server for SAP applications 16.0 Fixed
openSUSE Leap 15.6 Fixed
openSUSE Leap 16.0 Fixed

References

Advisories & patches
PATCH https://github.com/sigstore/fulcio/commit/eaae2f2be56df9dea5f9b439ec81bedae4c0978d ADVISORY https://access.redhat.com/errata/RHSA-2026:2136 ADVISORY https://access.redhat.com/errata/RHSA-2026:2144 ADVISORY https://access.redhat.com/errata/RHSA-2026:2922 ADVISORY https://access.redhat.com/errata/RHSA-2026:2924 ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:0592/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:0777/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20904/

Search Externally

GitHub PoC Exploit-DB PacketStorm Snyk Rapid7 Nuclei Templates Trickest PoC
Back

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy