# CVE-2026-44320: free5GC's NEF nnef-callback route group is unauthenticated; forged callback requests are accepted into the processing path > Attackers can forge callback requests to the NEF component due to missing authentication, potentially modifying subscription state. - **Severity:** High 7.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 27 May 2026 - **Updated:** 27 May 2026 - **Also known as:** GHSA-wqfh-gq79-j8mf, GO-2026-5717 ## What is CVE-2026-44320? CVE-2026-44320 is a high-severity missing authorization vulnerability in Free5gc Free5gc, published on 27 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description 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. Weakness: CWE-862 (Missing Authorization), CWE-306 (Missing Authentication for Critical Functionality) ## Which versions are affected by CVE-2026-44320? 3 open source packages ship an affected version, including github.com/free5gc/nef. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/free5gc/nef` | Go | All versions | None | | `github.com/free5gc/nef` | Go | All versions to 1.2.3 | None | | `github.com/free5gc/nef` | Go | All versions to 1.2.3 | None | Products: Free5gc Free5gc. ## How do I fix CVE-2026-44320? Upgrade to a fixed version. ## Is CVE-2026-44320 being exploited? There is no known exploitation of CVE-2026-44320 in the wild and no public exploit code. ## Other vulnerabilities in Free5gc Free5gc - [CVE-2026-44327](https://insights.sbomify.com/CVE-2026-44327/): free5GC: NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM handler (critical 10.0) - [CVE-2026-44329](https://insights.sbomify.com/CVE-2026-44329/): free5GC's SMF UPI management interface lacks auth middleware; unauthenticated topology read/write requests reach handlers (critical 10.0) - [CVE-2026-44330](https://insights.sbomify.com/CVE-2026-44330/): free5GC's NEF nnef-pfdmanagement API is unauthenticated; forged bearer tokens can read PFD data and create/delete PFD subscriptions (critical 10.0) - [CVE-2025-63679](https://insights.sbomify.com/CVE-2025-63679/): Memory corruption in n/a (critical 9.8) - [CVE-2026-44315](https://insights.sbomify.com/CVE-2026-44315/): free5GC's NEF 3gpp-pfd-management API is unauthenticated; forged bearer tokens can create, read, and delete PFD transactions (critical 9.4) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-44320 and fix it if it is affected. What it is: CVE-2026-44320 is a high-severity missing authorization vulnerability in Free5gc Free5gc, published on 27 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-44320 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/free5gc/nef (Go): affected all versions; no fix listed - github.com/free5gc/nef (Go): affected all versions up to 1.2.3; no fix listed - github.com/free5gc/nef (Go): affected all versions up to 1.2.3; no fix listed Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-44320/ (Markdown: https://insights.sbomify.com/CVE-2026-44320/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44320 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44320 - OSV: https://osv.dev/vulnerability/CVE-2026-44320 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-44320/ Summaries are generated and may contain mistakes; the official description above is the record.