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Open5gs CVE-2023-37021

HIGH
Reachable Assertion (CWE-617)
2025-01-22 cve@mitre.org
8.6
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V16 - Security Logging and Error Handling Reachable assertion handling
Impact

CVSS score of 8.6 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available. EPSS exploitation probability: 0.32%.

Exploit ScenarioDerived

This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the high-severity affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

Open5GS MME version <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. Rated high severity (CVSS 8.6), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Earlier versions of this analysis (1)
v1 Mar 28, 2026 - 18:05 CVSS 8.6

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

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

This vulnerability is classified under CWE-617. Open5GS MME version <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send a UE Context Modification Failure message missing a required MME_UE_S1AP_ID field to repeatedly crash the MME, resulting in denial of service. Affected products include: Open5Gs.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 8.6 HIGH
AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Lifecycle Timeline

2
PoC Detected
Apr 22, 2025 - 17:15 vuln.today
Public exploit code
CVE Published
Jan 22, 2025 - 15:15 nvd
HIGH 8.6

DescriptionCVE.org

Open5GS MME version <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send a UE Context Modification Failure message missing a required MME_UE_S1AP_ID field to repeatedly crash the MME, resulting in denial of service.

Executive ViewAI

Why It Matters

CVE-2023-37021 presents significant security risk rated CVSS 8.6. Successful exploitation could significantly impact the confidentiality, integrity, or availability of affected systems. Proof-of-concept code is publicly available, increasing the risk of exploitation. Organizations should apply vendor updates when available and consider compensating controls in the interim.

Business Impact: Severe
Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score
0.3%
Top 45% exploitable
Exploit
POC
Public exploit code exists
Data Quality
3 sources
Confidence: Low

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 0.3%
Patch available No
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
Very High

Priority Score

63
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +43
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)CVE.org

cpe:2.3:a:open5gs:open5gs:*:*:*:*:*:*:*:*
CVE-2025-15684 MEDIUM POC
5.5 Aug 12

Reachable assertion in Open5GS up to version 2.7.6 allows remote unauthenticated attackers to crash the Diameter CER han

CVE-2025-15687 LOW POC
2.1 Aug 12

Denial of service in Open5GS 2.7.6 and earlier allows network-adjacent attackers with low-privilege Diameter Gx peer acc

CVE-2025-15686 LOW POC
2.1 Aug 12

Denial of service in Open5GS HSS (Home Subscriber Server) versions 2.7.0 through 2.7.6 is triggered remotely by manipula

CVE-2024-40130 CRITICAL POC
9.8 Jul 16

open5gs v2.6.4 is vulnerable to Buffer Overflow. Rated critical severity (CVSS 9.8), this vulnerability is remotely expl

CVE-2024-40129 CRITICAL POC
9.8 Jul 16

Open5GS v2.6.4 is vulnerable to Buffer Overflow. Rated critical severity (CVSS 9.8), this vulnerability is remotely expl

CVE-2021-28122 CRITICAL POC
9.8 Mar 10

A request-validation issue was discovered in Open5GS 2.1.3 through 2.2.x before 2.2.1. Rated critical severity (CVSS 9.8

CVE-2025-15685 MEDIUM
5.3 Aug 12

Memory corruption in Open5GS versions through 2.7.1 is remotely exploitable via the freeDiameter protocol component, all

CVE-2021-25863 HIGH POC
8.8 Jan 26

Open5GS 2.1.3 listens on 0.0.0.0:3000 and has a default password of 1423 for the admin account. Rated high severity (CVS

CVE-2023-37023 HIGH POC
8.6 Jan 22

Open5GS MME versions <= 2.6.4 contain a reachable assertion in the `Uplink NAS Transport` packet handler. Rated high sev

CVE-2023-37020 HIGH POC
8.6 Jan 22

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the

CVE-2023-37019 HIGH POC
8.6 Jan 22

Open5GS MME versions <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the

CVE-2023-37018 HIGH POC
8.6 Jan 22

Open5GS MME versions <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the

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