CVE-2026-1976Public exploitNetwork attack vector

SMF crash via missing PFCP Cause check

Published Feb 6, 2026 · Updated Feb 6, 2026

Null pointer dereference in free5GC SMF 4.0 and 4.1.0 allows remote attackers to crash the service via a malformed PFCP response. The deletePfcpSession function reads rsp.Cause.CauseValue without first checking whether a SessionDeletionResponse contains the mandatory Cause IE. Exploitation requires a rogue or impersonated UPF to receive an SMF deletion request and return the crafted response, terminating the SMF process.

CVSS severity7.5
High
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Null pointer dereference in free5GC SMF 4.0 and 4.1.0 allows remote attackers to crash the service via a malformed PFCP response. The deletePfcpSession function reads rsp.Cause.CauseValue without first checking whether a SessionDeletionResponse contains the mandatory Cause IE. Exploitation requires a rogue or impersonated UPF to receive an SMF deletion request and return the crafted response, terminating the SMF process.

The record

CVE
CVE-2026-1976
Published
Feb 6, 2026
Updated
Feb 6, 2026
Vendor
free5GC
Product
free5GC
Classifications
CWE-476, CWE-404, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 6, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.0
  2. Affected versionversion=4.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

free5GC · free5GCversion=4.0; version=4.1.0

Published CVSS scores

5.5VulDB CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0VulDB CNAAV:N/AC:L/Au:N/C:N/I:N/A:P
5.3VulDB CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
CWE-404Improper Resource Shutdown or Release
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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