CVE-2026-8266Public exploitNetwork attack vector

Authenticated SMF crash via malformed QoS rules

Published May 11, 2026 · Updated May 11, 2026

Denial of service in Open5GS SMF 2.7.0 through 2.7.7 allows remote authenticated users to crash SMF via a crafted H-SMF response. gsm_build_pdu_session_establishment_accept trusts base64 QoS rules from PduSessionCreatedData and asserts when decoding returns no data. Exploitation requires control of an H-SMF response during home-routed roaming; one malformed response aborts SMF and interrupts session management.

CVSS severity6.5
Medium
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Open5GS SMF 2.7.0 through 2.7.7 allows remote authenticated users to crash SMF via a crafted H-SMF response. gsm_build_pdu_session_establishment_accept trusts base64 QoS rules from PduSessionCreatedData and asserts when decoding returns no data. Exploitation requires control of an H-SMF response during home-routed roaming; one malformed response aborts SMF and interrupts session management.

The record

CVE
CVE-2026-8266
Published
May 11, 2026
Updated
May 11, 2026
Vendor
Open5GS
Product
Open5GS
Classifications
CWE-404, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 11, 2026CVE publishedPublication date reported by the CVE source.
  2. May 11, 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
  8. Affected versionversion=2.7.7

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; version=2.7.7

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.0VulDB CNAAV:N/AC:L/Au:S/C:N/I:N/A:P
2.1VulDB CNACVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
4.3VulDB CNACVSS:3.1/AV:N/AC:L/PR:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

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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