CVE-2026-44320

HIGHNVD 7.37.3—
EchelonGraph scoreMEDIUM confidence

Score 7.3 from GitHub Security Advisory (severity: HIGH) published 2026-05-08. NVD baseline CVSS 7.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.3
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.3Exploit: NoneExposed: 0

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

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the nnef-callback route group without inbound OAuth2/bearer-token authorization. A forged or arbitrary bearer token (e.g. Authorization: Bearer not-a-real-token) is enough to reach the SMF-callback handler -- the callback body is parsed and dispatched into NEF business logic instead of being rejected at the auth boundary. Same root cause as the other NEF SBI findings: the route group is mounted without any inbound auth middleware. NEF does not authenticate the producer NF identity before processing callback content; if an attacker can guess or obtain a valid NotifId, this missing auth boundary lets forged callbacks act on real subscription state. The route group is also reachable even when the runtime ServiceList does not declare it (it lists only nnef-pfdmanagement and nnef-oam). This vulnerability is fixed in 4.2.2.

CVSS v3
7.3
EG Score
7.3(medium)
EPSS
15.3%
KEV
Not listed

Published

May 27, 2026

Last Modified

May 28, 2026

Advisory Details (3)

Auto-updated Jun 11, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_pr.
github Patch Available🟡 PoC Available

NEF nnef-callback route group is unauthenticated; forged callback requests are accepted into the processing path · Advisory · free5gc/free5gc · GitHub

https://github.com/free5gc/free5gc/security/advisories/GHSA-wqfh-gq79-j8mf
github_pr

fix(sbi): add inbound OAuth2 middleware to nnef-callback route

Upstream fix in progress (PR #24 · free5gc/nef, state=open)

https://github.com/free5gc/nef/pull/24
generic

[Bugs] NEF `nnef-callback` is unauthenticated: forged callback requests are accepted into the processing path · Issue #860 · free5gc/free5gc · GitHub

https://github.com/free5gc/free5gc/issues/860

Vendor Advisories for CVE-2026-44320(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
gogithub.com/free5gc/nef—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/free5gc/nef———

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 43× 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.

Showing the most recent 100 of 117 total refreshes for this CVE.

  1. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-21 15:24 UTCEPSS rescore
  3. 2026-07-20 17:08 UTCEPSS rescore
  4. 2026-07-19 02:29 UTCEPSS rescore
  5. 2026-07-18 10:04 UTCEPSS rescore
  6. 2026-07-16 17:03 UTCEPSS rescore
  7. 2026-07-15 16:57 UTCEPSS rescore
  8. 2026-07-15 02:00 UTCEPSS rescore
  9. 2026-07-13 22:30 UTCEPSS rescore
  10. 2026-07-13 06:13 UTCEPSS rescore
  11. 2026-07-12 05:46 UTCEPSS rescore
  12. 2026-07-11 23:17 UTCGHSA enrichment
  13. 2026-07-11 08:27 UTCEPSS rescore
  14. 2026-07-09 19:10 UTCEPSS rescore
  15. 2026-07-08 23:45 UTCGHSA enrichment
  16. 2026-07-08 15:16 UTCEPSS rescore
  17. 2026-07-07 13:46 UTCEPSS rescore
  18. 2026-07-06 16:27 UTCEPSS rescore
  19. 2026-07-06 02:23 UTCEPSS rescore
  20. 2026-07-05 02:30 UTCEPSS rescore
  21. 2026-07-04 06:31 UTCEPSS rescore
  22. 2026-07-03 00:23 UTCGHSA enrichment
  23. 2026-07-01 15:07 UTCEPSS rescore
  24. 2026-07-01 09:31 UTCGHSA enrichment
  25. 2026-06-30 23:22 UTCEPSS rescore
Show 75 more
  1. 2026-06-30 03:11 UTCGHSA enrichment
  2. 2026-06-29 14:06 UTCEPSS rescore
  3. 2026-06-29 14:06 UTCGHSA enrichment
  4. 2026-06-28 19:59 UTCGHSA enrichment
  5. 2026-06-28 14:07 UTCEPSS rescore
  6. 2026-06-28 07:24 UTCGHSA enrichment
  7. 2026-06-28 04:56 UTCEPSS rescore
  8. 2026-06-27 18:25 UTCGHSA enrichment
  9. 2026-06-27 05:43 UTCGHSA enrichment
  10. 2026-06-27 03:08 UTCEPSS rescore
  11. 2026-06-26 17:02 UTCGHSA enrichment
  12. 2026-06-26 02:22 UTCGHSA enrichment
  13. 2026-06-25 13:49 UTCEPSS rescore
  14. 2026-06-25 13:49 UTCEPSS rescore
  15. 2026-06-25 13:08 UTCGHSA enrichment
  16. 2026-06-25 00:25 UTCGHSA enrichment
  17. 2026-06-24 14:05 UTCEPSS rescore
  18. 2026-06-23 21:33 UTCEPSS rescore
  19. 2026-06-22 14:25 UTCEPSS rescore
  20. 2026-06-22 14:25 UTCEPSS rescore
  21. 2026-06-21 14:56 UTCEPSS rescore
  22. 2026-06-21 14:56 UTCEPSS rescore
  23. 2026-06-21 01:59 UTCEPSS rescore
  24. 2026-06-19 19:25 UTCEPSS rescore
  25. 2026-06-18 17:52 UTCEPSS rescore
  26. 2026-06-18 17:52 UTCEPSS rescore
  27. 2026-06-17 18:36 UTCGHSA enrichment
  28. 2026-06-17 17:53 UTCEPSS rescore
  29. 2026-06-17 04:49 UTCGHSA enrichment
  30. 2026-06-16 17:52 UTCEPSS rescore
  31. 2026-06-16 16:00 UTCGHSA enrichment
  32. 2026-06-16 01:59 UTCGHSA enrichment
  33. 2026-06-15 17:49 UTCEPSS rescore
  34. 2026-06-15 13:25 UTCGHSA enrichment
  35. 2026-06-14 21:44 UTCGHSA enrichment
  36. 2026-06-14 09:10 UTCGHSA enrichment
  37. 2026-06-13 23:00 UTCEPSS rescore
  38. 2026-06-13 20:34 UTCGHSA enrichment
  39. 2026-06-13 02:50 UTCGHSA enrichment
  40. 2026-06-12 23:12 UTCEPSS rescore
  41. 2026-06-12 23:12 UTCEPSS rescore
  42. 2026-06-12 14:12 UTCGHSA enrichment
  43. 2026-06-12 01:37 UTCGHSA enrichment
  44. 2026-06-11 14:00 UTCEPSS rescore
  45. 2026-06-11 13:03 UTCGHSA enrichment
  46. 2026-06-11 00:27 UTCGHSA enrichment
  47. 2026-06-10 22:18 UTCEPSS rescore
  48. 2026-06-10 13:22 UTCEPSS rescore
  49. 2026-06-10 13:22 UTCEPSS rescore
  50. 2026-06-10 11:52 UTCGHSA enrichment
  51. 2026-06-09 23:18 UTCGHSA enrichment
  52. 2026-06-09 10:43 UTCGHSA enrichment
  53. 2026-06-08 22:09 UTCGHSA enrichment
  54. 2026-06-08 14:17 UTCEPSS rescore
  55. 2026-06-08 14:17 UTCEPSS rescore
  56. 2026-06-08 09:33 UTCGHSA enrichment
  57. 2026-06-07 20:58 UTCGHSA enrichment
  58. 2026-06-07 15:25 UTCEPSS rescore
  59. 2026-06-07 15:25 UTCEPSS rescore
  60. 2026-06-07 08:23 UTCGHSA enrichment
  61. 2026-06-06 19:49 UTCGHSA enrichment
  62. 2026-06-06 13:47 UTCEPSS rescore
  63. 2026-06-06 13:47 UTCEPSS rescore
  64. 2026-06-06 07:15 UTCGHSA enrichment
  65. 2026-06-05 22:47 UTCEPSS rescore
  66. 2026-06-05 18:40 UTCGHSA enrichment
  67. 2026-06-05 06:10 UTCEPSS rescore
  68. 2026-06-05 06:10 UTCEPSS rescore
  69. 2026-06-05 06:05 UTCGHSA enrichment
  70. 2026-06-04 17:30 UTCGHSA enrichment
  71. 2026-06-04 13:12 UTCEPSS rescore
  72. 2026-06-04 13:12 UTCEPSS rescore
  73. 2026-06-04 04:55 UTCGHSA enrichment
  74. 2026-06-03 16:20 UTCGHSA enrichment
  75. 2026-06-03 03:45 UTCGHSA enrichment

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-44320?
CVE-2026-44320 is a high vulnerability published on May 27, 2026. free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the nnef-callback route group without inbound OAuth2/bearer-token authorization. A forged or arbitrary bearer token (e.g. Authorization: Bearer not-a-real-token) is enough to reach the SMF-callback…
When was CVE-2026-44320 disclosed?
CVE-2026-44320 was first published in the National Vulnerability Database on May 27, 2026, with the most recent update on May 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-44320 actively exploited?
CVE-2026-44320 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 15.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-44320?
CVE-2026-44320 has a CVSS v3 base score of 7.3 (NVD).
How do I remediate CVE-2026-44320?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-44320, 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.

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