CVE-2026-4988Public exploitNetwork attack vector

SMF crash via unknown Diameter Session-Id

Published Mar 27, 2026 · Updated Mar 27, 2026

Denial of service in the CCA message handlers in Open5GS 2.7.6 allows remote attackers to crash the SMF via a crafted Diameter response. The smf_gx_cca_cb, smf_gy_cca_cb, and smf_s6b callbacks assert that fd_msg_sess_get found an existing session, so an unknown or mismatched Session-Id causes ogs_abort to terminate the process. The attacker must operate a configured or substituted Diameter peer able to answer an SMF request; one response interrupts all UE sessions handled by that SMF.

CVSS severity5.9
Medium
EPSS probability0.57%
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 the CCA message handlers in Open5GS 2.7.6 allows remote attackers to crash the SMF via a crafted Diameter response. The smf_gx_cca_cb, smf_gy_cca_cb, and smf_s6b callbacks assert that fd_msg_sess_get found an existing session, so an unknown or mismatched Session-Id causes ogs_abort to terminate the process. The attacker must operate a configured or substituted Diameter peer able to answer an SMF request; one response interrupts all UE sessions handled by that SMF.

The record

CVE
CVE-2026-4988
Published
Mar 27, 2026
Updated
Mar 27, 2026
Vendor
Open5GS
Product
Open5GS
Classifications
CWE-404, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 27, 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=2.7.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Open5GS · Open5GSversion=2.7.6

Published CVSS scores

2.6VulDBAV:N/AC:H/Au:N/C:N/I:N/A:P
2.9VulDBCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
5.9NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
3.7VulDBCVSS:3.1/AV:N/AC:H/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 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-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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