How severe is CVE-2026-4240?

CVE-2026-4240 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2026-4240 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-4240?

CVE-2026-4240 affects Open5gs. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-4240?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-4240 have an EU (EUVD) identifier?

Yes. CVE-2026-4240 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12433.

When was CVE-2026-4240 published?

CVE-2026-4240 was published on 2026-03-16 and last updated on 2026-06-17.

CVE-2026-4240

CVE-2026-4240 is a medium-severity vulnerability in Open5gs with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-404.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
CVSS v4: 5.5
EPSS exploit prediction: 1% (41st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-12433
Weakness: CWE-404
Affected product: Open5gs
Published: 2026-03-16
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-4240?: 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.
How severe is CVE-2026-4240?: CVE-2026-4240 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2026-4240 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-4240?: CVE-2026-4240 affects Open5gs. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-4240?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-4240 have an EU (EUVD) identifier?: Yes. CVE-2026-4240 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12433.
When was CVE-2026-4240 published?: CVE-2026-4240 was published on 2026-03-16 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:open5gs:open5gs:*:*:*:*:*:*:*:*

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