CVE-2026-44318

CVE-2026-44318 is a medium-severity race condition vulnerability in github.com/free5gc/bsf (go), affecting versions < 1.0.2. It is fixed in 1.0.2.

Summary

free5GC's BSF concurrent PUT /nbsf-management/v1/subscriptions/{subId} crashes the BSF process via concurrent map read/write on Subscriptions

Impact

Unsynchronized concurrent access (CWE-362) to a shared map (BsfSelf.Subscriptions), combined with missing synchronization on the create-if-absent branch (CWE-820). Go's runtime detects concurrent map read/write and terminates the process via a non-recoverable fatal error -- Gin's recover() middleware does NOT catch this class of fatal, unlike ordinary nil-deref panics. The whole BSF process exits, dropping BSF's nbsf-management SBI surface (PCF binding lookups for SMF, AF -> PCF binding discovery, etc.) until restart.

Any party that holds (or can obtain) a valid nbsf-management token can:

  • Drive the create-if-absent code path at high concurrency by PUTting a stream of fresh subId values, deterministically tripping the runtime fatal and killing the BSF process.
  • Repeat the trigger after every restart to sustain the outage.

No Confidentiality impact (the crash returns no attacker-readable data). No persistent Integrity impact (BSF subscription state is in-memory and is lost when the process dies). The whole impact concentrates in Availability: complete loss of BSF service via concurrent attacker traffic on a single endpoint.

Affected: free5gc v4.2.1.

Upstream issue: https://github.com/free5gc/free5gc/issues/926
Upstream fix: https://github.com/free5gc/bsf/pull/7

Multiple concurrent operations access a shared resource without proper synchronization, producing unpredictable results depending on timing. Typical impact: TOCTOU exploits, data corruption, or privilege escalation.

CVE-2026-44318 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.0.2); upgrading removes the vulnerable code path.

Affected versions

github.com/free5gc/bsf (< 1.0.2)

Security releases

github.com/free5gc/bsf → 1.0.2 (go)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Upgrade github.com/free5gc/bsf to 1.0.2 or later to resolve this vulnerability.

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

  1. What is CVE-2026-44318? CVE-2026-44318 is a medium-severity race condition vulnerability in github.com/free5gc/bsf (go), affecting versions < 1.0.2. It is fixed in 1.0.2. Multiple concurrent operations access a shared resource without proper synchronization, producing unpredictable results depending on timing.
  2. How severe is CVE-2026-44318? CVE-2026-44318 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
  3. Which versions of github.com/free5gc/bsf are affected by CVE-2026-44318? github.com/free5gc/bsf (go) versions < 1.0.2 is affected.
  4. Is there a fix for CVE-2026-44318? Yes. CVE-2026-44318 is fixed in 1.0.2. Upgrade to this version or later.
  5. Is CVE-2026-44318 exploitable, and should I be worried? Whether CVE-2026-44318 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
  6. What actually determines whether CVE-2026-44318 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
  7. How do I fix CVE-2026-44318? Upgrade github.com/free5gc/bsf to 1.0.2 or later.

Other vulnerabilities in github.com/free5gc/bsf

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