Security Digest · Vulnerability record
CVE-2025-66719: Free5gc NRF is vulnerable to scope validation bypass via maliciously crafted targetNF value
An issue was discovered in Free5gc NRF 1.4.0.
CVSS 9.1 Critical EPSS 0.4% · p29
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.4%, percentile 29: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 29% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
github.com/free5gc/nrf(Go) < 1.4.1, fixed in 1.4.1. Check your lockfile, including transitive dependencies.
What it is
An issue was discovered in Free5gc NRF 1.4.0. In the access-token generation logic of free5GC, the AccessTokenScopeCheck() function in file internal/sbi/processor/accesstoken.go bypasses all scope validation when the attacker uses a crafted targetNF value. This allows attackers to obtain an access token with any arbitrary scope.
From the GitHub advisory
An issue was discovered in Free5gc NRF 1.4.0. In the access-token generation logic of free5GC, the AccessTokenScopeCheck() function in file internal/sbi/processor/accesstoken.go bypasses all scope validation when the attacker uses a crafted targetNF value. This allows attackers to obtain an access token with any arbitrary scope.
Weakness type: CWE-863.
Product: github.com/free5gc/nrf (Go) · Assigned by: mitre · Published: 2026-01-23
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Go | github.com/free5gc/nrf | < 1.4.1 | 1.4.1 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| n/a | n/a | see vendor advisory |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADP | 3.1 | 9.1 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| GitHub | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable yes, technical impact partial.
- FIRST EPSS (model of 2026-10-21): 0.36% probability of exploitation activity in the next 30 days; percentile 29.
Timeline
- — CVE record last updated
- — CVE record published by mitre
- — GitHub-reviewed advisory GHSA-q7c8-gfjh-8v4p published (critical)
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-q7c8-gfjh-8v4p github.com
- CVE.org record CVE-2025-66719 cve.org
- NVD entry CVE-2025-66719 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com