CVE-2026-4240

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 57% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
38(Track)
EG Risk 38/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
44%
KEV
Not listed

Published

March 16, 2026

Last Modified

June 17, 2026

Advisory Details (5)

Auto-updated Aug 2, 2026
Patch available. Sources: github_commit, github_release.
github_release Patch Available

v2.7.7

Patch available: open5gs/open5gs v2.7.7

https://github.com/open5gs/open5gs/releases/tag/v2.7.7
generic

[Bug]: MME S6a AIA Origin-Host validation bypass allows authentication vector injection and full session key takeover · Issue #4343 · open5gs/open5gs · GitHub

https://github.com/open5gs/open5gs/issues/4343#issue-4021871895
generic

[Bug]: MME S6a AIA Origin-Host validation bypass allows authentication vector injection and full session key takeover · Issue #4343 · open5gs/open5gs · GitHub

https://github.com/open5gs/open5gs/issues/4343
github_commit Patch Available

commit 80eb484a6ab3 (open5gs/open5gs)

Patch available: open5gs/open5gs v2.7.7 (contains commit 80eb484a6ab3)

https://github.com/open5gs/open5gs/commit/80eb484a6ab32968e755e628b70d1a9c64f012ec
generic

GitHub - open5gs/open5gs: Open5GS is a C-language Open Source implementation for 5G Core and EPC, i.e. the core network of LTE/NR network (Release-19) · GitHub

https://github.com/open5gs/open5gs/

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 4× in last 7d / 22× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-16 14:08 UTCEPSS rescore
  3. 2026-09-16 05:15 UTCEPSS rescore
  4. 2026-09-13 16:47 UTCEPSS rescore
  5. 2026-09-11 14:53 UTCEPSS rescore
  6. 2026-09-10 09:35 UTCEPSS rescore
  7. 2026-09-08 22:01 UTCEPSS rescore
  8. 2026-09-07 16:01 UTCEPSS rescore
  9. 2026-09-06 13:47 UTCEPSS rescore
  10. 2026-09-04 05:06 UTCEPSS rescore
  11. 2026-09-02 18:38 UTCOSV refresh
  12. 2026-09-02 14:12 UTCEPSS rescore
  13. 2026-09-01 13:54 UTCEPSS rescore
  14. 2026-09-01 04:40 UTCEPSS rescore
  15. 2026-08-30 19:17 UTCEPSS rescore
  16. 2026-08-30 01:22 UTCEPSS rescore
  17. 2026-08-28 21:41 UTCEPSS rescore
  18. 2026-08-27 14:25 UTCEPSS rescore
  19. 2026-08-26 14:46 UTCEPSS rescore
  20. 2026-08-25 13:49 UTCEPSS rescore
  21. 2026-08-23 00:19 UTCEPSS rescore
  22. 2026-08-21 23:49 UTCEPSS rescore
  23. 2026-08-20 22:55 UTCEPSS rescore
  24. 2026-08-19 17:04 UTCEPSS rescore
  25. 2026-08-18 13:48 UTCEPSS rescore
Show 49 more
  1. 2026-08-17 13:47 UTCEPSS rescore
  2. 2026-08-16 14:56 UTCEPSS rescore
  3. 2026-08-16 11:25 UTCEG score recompute
  4. 2026-08-16 11:25 UTCGHSA enrichment
  5. 2026-08-16 02:14 UTCEPSS rescore
  6. 2026-08-15 01:30 UTCEPSS rescore
  7. 2026-08-14 20:00 UTCGHSA enrichment
  8. 2026-08-14 07:31 UTCEG score recompute
  9. 2026-08-14 07:31 UTCGHSA enrichment
  10. 2026-08-13 22:00 UTCEPSS rescore
  11. 2026-08-12 22:19 UTCEG score recompute
  12. 2026-08-12 22:19 UTCGHSA enrichment
  13. 2026-08-12 13:51 UTCEPSS rescore
  14. 2026-08-11 21:35 UTCEG score recompute
  15. 2026-08-11 21:35 UTCGHSA enrichment
  16. 2026-08-11 04:43 UTCEG score recompute
  17. 2026-08-11 04:43 UTCGHSA enrichment
  18. 2026-08-11 00:00 UTCEPSS rescore
  19. 2026-08-10 07:33 UTCGHSA enrichment
  20. 2026-08-09 19:20 UTCEG score recompute
  21. 2026-08-09 19:20 UTCGHSA enrichment
  22. 2026-08-09 13:46 UTCEPSS rescore
  23. 2026-08-09 07:07 UTCEG score recompute
  24. 2026-08-09 07:07 UTCGHSA enrichment
  25. 2026-08-08 16:37 UTCEPSS rescore
  26. 2026-08-08 05:57 UTCGHSA enrichment
  27. 2026-08-07 17:44 UTCEG score recompute
  28. 2026-08-07 17:44 UTCGHSA enrichment
  29. 2026-08-06 19:36 UTCEG score recompute
  30. 2026-08-06 19:36 UTCGHSA enrichment
  31. 2026-08-06 13:47 UTCEPSS rescore
  32. 2026-08-06 01:46 UTCEG score recompute
  33. 2026-08-06 01:46 UTCGHSA enrichment
  34. 2026-08-05 19:17 UTCEPSS rescore
  35. 2026-08-04 15:10 UTCEPSS rescore
  36. 2026-08-04 10:39 UTCEPSS rescore
  37. 2026-08-04 00:56 UTCEG score recompute
  38. 2026-08-04 00:56 UTCGHSA enrichment
  39. 2026-08-03 10:36 UTCEPSS rescore
  40. 2026-08-02 16:56 UTCEG score recompute
  41. 2026-08-02 16:56 UTCGHSA enrichment
  42. 2026-08-02 02:27 UTCEPSS rescore
  43. 2026-08-01 04:16 UTCEPSS rescore
  44. 2026-07-30 16:28 UTCEPSS rescore
  45. 2026-07-30 01:30 UTCEPSS rescore
  46. 2026-07-28 15:37 UTCEPSS rescore
  47. 2026-07-27 14:43 UTCEG score recompute
  48. 2026-07-27 14:43 UTCGHSA enrichment
  49. 2026-07-27 14:27 UTCOSV refresh

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-4240?
CVE-2026-4240 is a high vulnerability published on March 16, 2026. A vulnerability was determined in Open5GS up to 2.7.6. The affected element is the function smfgxccacb/smfgyccacb/smfs6baaacb/smfs6bstacb 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…
When was CVE-2026-4240 disclosed?
CVE-2026-4240 was first published in the National Vulnerability Database on March 16, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4240 actively exploited?
CVE-2026-4240 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 56.0% of all scored CVEs.
What is the CVSS score of CVE-2026-4240?
CVE-2026-4240 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-4240?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4240, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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