CVE-2026-8743Public exploitNetwork attack vector

Downlink traffic redirection via unscoped UE lookup

Published May 17, 2026 · Updated May 17, 2026

Improper authorization in Open5GS AMF/MME 2.7.0 through 2.7.6 allows remote authenticated users to redirect victim downlink traffic. The AMF resolves AMF-UE-NGAP-ID through a process-wide pool and accepts a session response without verifying that its sending gNB owns the resolved UE context. An attacker-controlled gNB with an established NG connection can supply another UE's identifiers and endpoint, causing the UPF to forward that UE's downlink traffic to the attacker.

CVSS severity6.3
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in Open5GS AMF/MME 2.7.0 through 2.7.6 allows remote authenticated users to redirect victim downlink traffic. The AMF resolves AMF-UE-NGAP-ID through a process-wide pool and accepts a session response without verifying that its sending gNB owns the resolved UE context. An attacker-controlled gNB with an established NG connection can supply another UE's identifiers and endpoint, causing the UPF to forward that UE's downlink traffic to the attacker.

The record

CVE
CVE-2026-8743
Published
May 17, 2026
Updated
May 17, 2026
Vendor
Open5GS
Product
Open5GS
Classifications
CWE-285, CWE-266, T1040
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 17, 2026CVE publishedPublication date reported by the CVE source.
  2. May 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=2.7.0
  2. Affected versionversion=2.7.1
  3. Affected versionversion=2.7.2
  4. Affected versionversion=2.7.3
  5. Affected versionversion=2.7.4
  6. Affected versionversion=2.7.5
  7. Affected versionversion=2.7.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Open5GS · Open5GSversion=2.7.0; version=2.7.1; version=2.7.2; version=2.7.3; version=2.7.4; version=2.7.5; version=2.7.6

Published CVSS scores

2.1VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
6.3VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
6.5VulDBAV:N/AC:L/Au:S/C:P/I:P/A:P

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

Weakness, pattern, technique

CWE-285Improper Authorization
CWE-266Incorrect Privilege Assignment
T1040Network Sniffing

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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