CVE-2026-4240

Name: CVE-2026-4240
Creator: NVD / NIST
Published: 2026-03-16T14:20:18.963+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 0.53%

Last modified Jun 17, 2026

CVE-2026-4240 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. A vulnerability was determined in Open5GS up to 2.7.6. The affected element is the function smf_gx_cca_cb/smf_gy_cca_cb/smf_s6b_aaa_cb/smf_s6b_sta_cb of the component CCA Handler. EPSS estimates a 0.53% chance of exploitation in the next 30 days.

Description

A vulnerability was determined in Open5GS up to 2.7.6. The affected element is the function smf_gx_cca_cb/smf_gy_cca_cb/smf_s6b_aaa_cb/smf_s6b_sta_cb of the component CCA Handler. This manipulation causes denial of service. The attack can be initiated remotely. The exploit has been publicly disclosed and may be utilized. Upgrading to version 2.7.7 is sufficient to fix this issue. Patch name: 80eb484a6ab32968e755e628b70d1a9c64f012ec. Upgrading the affected component is recommended.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS 4.0

5.5/10

CVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.53%

41.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-404

Affected Software

Vendor	Product	Versions
Open5gs	Open5gs	< 2.7.7

References

https://github.com/open5gs/open5gs/Product
https://github.com/open5gs/open5gs/commit/80eb484a6ab32968e755e628b70d1a9c64f012ecPatch
https://github.com/open5gs/open5gs/issues/4343Issue Tracking, Third Party Advisory
https://github.com/open5gs/open5gs/issues/4343#issue-4021871895Exploit, Issue Tracking, Third Party Advisory
https://github.com/open5gs/open5gs/releases/tag/v2.7.7Release Notes
https://vuldb.com/?ctiid.351182Permissions Required, VDB Entry
https://vuldb.com/?id.351182Third Party Advisory, VDB Entry
https://vuldb.com/?submit.771361Exploit, Third Party Advisory, VDB Entry

Timeline

Published: Mar 16, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-4240?

How severe is CVE-2026-4240?

CVE-2026-4240 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.53% probability of exploitation in the next 30 days.

How do I fix CVE-2026-4240?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-4240?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST