Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-1976 is a medium-severity Improper Resource Shutdown or Release (CWE-404) vulnerability in Free5Gc Free5Gc. Its CVSS base score is 5.5 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 42th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-1976 is a null pointer dereference vulnerability (CWE-404, CWE-476) affecting the SessionDeletionResponse function in the SMF component of Free5GC versions up to 4.1.0. This flaw allows remote manipulation, resulting in a denial-of-service condition due to improper handling that leads to a crash. The vulnerability carries a CVSS v3.1 base score of 5.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L), indicating medium severity with low complexity and no requirements for privileges or user interaction.
The vulnerability can be exploited remotely by unauthenticated attackers over the network with low effort. Successful exploitation triggers a null pointer dereference, causing the SMF component to crash and disrupt service availability, though it does not compromise confidentiality or integrity.
Advisories recommend installing a patch to mitigate the issue, with details available in Free5GC GitHub issue #817 and the corresponding pull request in the smf repository (free5gc/smf/pull/189). An exploit has been publicly disclosed and could be adapted for attacks.
Free5GC is an open-source implementation of 5G core network functions, making this vulnerability relevant to deployments relying on its SMF for session management.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-5602
Vulnerability Data
A weakness has been identified in Free5GC up to 4.1.0. Affected is the function SessionDeletionResponse of the component SMF. This manipulation causes null pointer dereference. The attack is possible to be carried out remotely. The exploit has been made available…
more
to the public and could be used for attacks. It is suggested to install a patch to address this issue.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover missing or incorrect resource releases after code is written.
Documented development standards and tools can enforce null-safety rules and safe pointer usage.
Engineering principles can require explicit resource acquisition/release patterns that stop improper shutdown from being introduced.
Priority-based resource allocation limits the blast radius when released resources are not returned to the pool.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly include coding standards for correct resource allocation and release.
Runtime monitoring can detect resource exhaustion caused by improper shutdown or release.
Lifecycle management of assets can encompass proper resource release at end-of-life or shutdown.
Capacity management helps surface leaks from unreleased resources but does not prevent the coding flaw.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect NULL dereference defects before release.
Including restart, recovery and media-handling instructions reduces the likelihood that resources or sensitive data will be left in an exposed or improperly released state after a failure.
Secure SDLC mandates defensive coding practices that can prevent NULL dereferences.
Application security requirements can specify input validation and pointer-safety rules.
Secure architecture principles encourage defensive design that avoids unsafe pointer use.
Secure coding standards directly require NULL-pointer checks and safe dereference patterns.