CVE-2026-22772 | Fulcio vulnerable to Server-Side Request Forgery (SSRF) via MetaIssuer Regex Bypass

Exp

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.

Published: 2026-01-12 Last update: 2026-03-05 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-22772 is rated Exploit Available (50/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.02%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-22772

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-22772

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-01-13 — 0.02% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-22772

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.8 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]

Weakness enumeration for CVE-2026-22772

GitHub Security Advisory for CVE-2026-22772

GHSA-59jp-pj84-45mr · Severity: medium · Ecosystem: go — Fulcio is vulnerable to Server-Side Request Forgery (SSRF) via MetaIssuer Regex Bypass

OS Trackers for CVE-2026-22772

vendor priority summary link
debian not yet assigned CVE-2026-22772 not yet assigned priority: Debian including 1 source packages (golang-github-sigstore-fulcio), 3 status rows across 3 suites (forky, sid, trixie): resolved 2, open 1. https://security-tracker.debian.org/tracker/CVE-2026-22772
redhat medium — https://access.redhat.com/security/cve/CVE-2026-22772
suse medium CVE-2026-22772 severity moderate: SUSE including 37 source package names (apptainer, apptainer-leap, …), 219 product×package rows across 60 product lines (Image SL-Micro, Image SL-Micro-Azure, … (60 product lines)): Known Not Affected 168, Fixed 50, First Fixed 1. https://www.suse.com/security/cve/CVE-2026-22772/
ubuntu medium CVE-2026-22772 medium priority: Ubuntu including 1 source packages (golang-github-sigstore-fulcio), 5 status rows across 5 suites (jammy, noble, plucky, questing, upstream): DNE 2, needs-triage 2, ignored 1. https://ubuntu.com/security/CVE-2026-22772

Affected software / configurations for CVE-2026-22772

Vendor Product Version Raw CPE
linuxfoundation fulcio < 1.8.5 cpe:2.3:a:linuxfoundation:fulcio:*:*:*:*:*:*:*:*

References for CVE-2026-22772

cvelogic Threat Intelligence