CVE-2023-37021Network attack vector

Remote MME crash via asserted error response

Published Jan 22, 2025 · Updated Feb 6, 2025

Reachable assertion in Open5GS MME 2.6.4 and earlier allows remote attackers to crash the MME with a malformed S1AP message. In s1ap_handle_ue_context_modification_failure(), a missing MME_UE_S1AP_ID enters error handling that asserts the error response succeeds. Access to S1AP, including through a connected base station or an exposed Wi-Fi Calling path, permits repeated MME crashes and cellular service interruption without a SIM.

CVSS severity8.6
High
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in Open5GS MME 2.6.4 and earlier allows remote attackers to crash the MME with a malformed S1AP message. In s1ap_handle_ue_context_modification_failure(), a missing MME_UE_S1AP_ID enters error handling that asserts the error response succeeds. Access to S1AP, including through a connected base station or an exposed Wi-Fi Calling path, permits repeated MME crashes and cellular service interruption without a SIM.

The record

CVE
CVE-2023-37021
Published
Jan 22, 2025
Updated
Feb 6, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 22, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 6, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.6CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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