CVE-2026-71676Public exploitNetwork attack vector

AMF service crash via NAS type confusion

Published Aug 18, 2026 · Updated Aug 19, 2026

Heap-buffer overflow in the Open5GS AMF 2.7.2 and earlier allows remote attackers to crash the service through a crafted NAS PDU. The NAS 5GS decoder treats a mutated Authentication Response as Service Accept data, and ogs_nas_5gs_decode_gprs_timer_2 reads one byte beyond the packet's heap buffer. Network access to the AMF N2 interface and the ability to send an NGAP UplinkNASTransport message while posing as a gNB are required; the resulting abort interrupts the AMF service.

CVSS severity7.5
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-buffer overflow in the Open5GS AMF 2.7.2 and earlier allows remote attackers to crash the service through a crafted NAS PDU. The NAS 5GS decoder treats a mutated Authentication Response as Service Accept data, and ogs_nas_5gs_decode_gprs_timer_2 reads one byte beyond the packet's heap buffer. Network access to the AMF N2 interface and the ability to send an NGAP UplinkNASTransport message while posing as a gNB are required; the resulting abort interrupts the AMF service.

The record

CVE
CVE-2026-71676
Published
Aug 18, 2026
Updated
Aug 19, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-122, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record 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

7.5CISA ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 exploitPublished

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1499.004Application or System Exploitation

Public exploit references

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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