What is the CVSS score of CVE-2026-27642?

CVE-2026-27642 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.1%.

Is there a public PoC exploit available for CVE-2026-27642?

Yes, a public proof-of-concept exploit is available for CVE-2026-27642. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2026-27642?

Within 24 hours: Identify all systems running affected free5GC UDM versions and isolate them from production if patching cannot be completed immediately. Within 7 days: Apply the available vendor patch to all UDM instances and conduct post-patch validation testing. Within 30 days: Perform full security audit of UDM access logs for signs of exploitation and review network segmentation controls around UDM infrastructure.

Free5gc CVE-2026-27642

HIGH

Improper Input Validation (CWE-20)

2026-02-24 security-advisories@github.com

Code Injection Free5gc Udm

7.5

CVSS 3.1 · GitHub Advisory

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Send HTTP request with control character in supi parameter
Exploit

Trigger URL parsing error in net/url
Execution

Expose system error details
Impact

Fingerprint free5GC UDM service

Vulnerability Assessment

Weakness	CWE CWE-20 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V2 - Validation and Business Logic Input validation, allowlisting
Exploitation Conditions	free5GC UDM service versions up to 1.4.1 with Nudm_UEAU service enabled. Remote unauthenticated attacker can inject control characters (e.g., %00) into supi parameter without authentication required.
Impact	CVSS 7.5 (HIGH). 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 Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Remote attackers can inject control characters into the SUPI parameter of free5GC UDM versions up to 1.4.1, causing URL parsing failures that leak sensitive system error details and enable service fingerprinting. Public exploit code exists for this vulnerability affecting the Nudm_UEAU service across all vulnerable deployments. A patch is available and should be applied immediately, as no application-level workaround exists.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:55 CVSS 7.5

free5gc UDM provides Unified Data Management (UDM) for free5GC, an open-source project for 5th generation (5G) mobile core networks. [CVSS 7.5 HIGH]

RemediationAI

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

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

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

Technical ContextAI · show details

Classified as CWE-20 (Improper Input Validation). Affects Udm. free5gc UDM provides Unified Data Management (UDM) for free5GC, an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.1, remote attackers can inject control characters (e.g., %00) into the supi parameter, triggering internal URL parsing errors (net/url: invalid control character). This exposes system-level error details and can be used for service fingerprinting. All deployments of free5GC using the UDM Nudm_UEAU service may be affected. free5gc

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 7.5 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Lifecycle Timeline

PoC Detected

Feb 25, 2026 - 16:44 vuln.today

Public exploit code

Patch released

Feb 25, 2026 - 16:44 nvd

Patch available

CVE Published

Feb 24, 2026 - 01:16 nvd

HIGH 7.5

DescriptionGitHub Advisory

free5gc UDM provides Unified Data Management (UDM) for free5GC, an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.1, remote attackers can inject control characters (e.g., %00) into the supi parameter, triggering internal URL parsing errors (net/url: invalid control character). This exposes system-level error details and can be used for service fingerprinting. All deployments of free5GC using the UDM Nudm_UEAU service may be affected. free5gc/udm pull request 75 contains a fix for the issue. No direct workaround is available at the application level. Applying the official patch is recommended.

Executive ViewAI

Why It Matters

A high-severity vulnerability (CVE-2026-27642) affecting free5GC's Unified Data Management component poses a significant risk to organizations operating 5G core network infrastructure. With a public exploit available and active exploitation possible, immediate patching is critical to prevent unauthorized access to subscriber data and network disruption.

Business Impact: High

Compensating Controls

Apply vendor patch. If immediate patching is delayed: implement strict network segmentation restricting UDM access to authenticated management networks only; enable enhanced logging and monitoring for UDM authentication and data access events; deploy WAF rules to block known exploit payloads if applicable; restrict UDM administrative interfaces to specific IP ranges.

Threat Intelligence Overview

EPSS Score

0.1%

Top 81% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

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 HIGH

CISA KEV No

Public POC Yes

EPSS 0.1%

Patch available Yes

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

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

Out-of-Cycle

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +38

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Code Injection CRITICAL

Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.