CVE-2026-1973VulnerabilityPublished 6 Feb 2026Updated 23 Feb 2026

CVE-2026-1973: Free5GC · NULL Pointer Dereference

Affects Free5GCSource CVE Database V5

Not known to be exploited · CVSS 6.9 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score

6.9Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.6% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Free5GC	Affected =4.0 =4.1.0	Fixed in–
GitHubfree5gc/free5gc`pkg:github/free5gc/free5gc`Other threats	Affected =4.0 =4.1.0	Fixed in–

CPE configurations (1)

cpe:2.3:a:free5gc:free5gc:*:*:*:*:*:*:*:*

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AI-suggested

1. Apply official patches or updates from the Free5GC project as soon as they become available to address the null pointer dereference in establishPfcpSession. 2. Until patches are deployed, implement network segmentation to isolate Free5GC SMF components from untrusted networks and restrict PFCP traffic to trusted sources only. 3. Deploy intrusion detection/prevention systems (IDS/IPS) with signatures or anomaly detection rules targeting malformed PFCP messages that could trigger the vulnerability. 4. Monitor SMF component logs and system health metrics for signs of crashes or abnormal behavior indicative of exploitation attempts. 5. Conduct regular security assessments and penetration testing focused on 5G core network components to identify and remediate similar vulnerabilities proactively. 6. Engage with Free5GC community and security advisories to stay informed about updates and emerging threats related to this vulnerability. 7. Consider implementing redundancy and failover mechanisms for SMF instances to minimize service disruption in case of exploitation.

Description

A vulnerability was determined in Free5GC up to 4.1.0. The impacted element is the function establishPfcpSession of the component SMF. Executing a manipulation can lead to null pointer dereference. The attack may be launched remotely. The exploit has been publicly disclosed and may be utilized. It is best practice to apply a patch to resolve this issue.

Impact

The primary impact of CVE-2026-1973 is on the availability of 5G core network services relying on Free5GC. A successful exploitation can cause the SMF component to crash or become unresponsive due to null pointer dereference, resulting in denial of service. This disruption can affect user session management and packet forwarding control, potentially degrading or interrupting 5G network connectivity for subscribers. Given the critical role of SMF in 5G networks, prolonged outages could impact telecom service providers' operational capabilities and customer experience. While the vulnerability does not directly expose sensitive data or allow unauthorized access, the service disruption could indirectly affect business continuity and emergency communications. Organizations deploying Free5GC in production environments face increased operational risk until the vulnerability is patched. The medium severity rating reflects the balance between ease of exploitation and limited scope of impact, but the critical nature of 5G infrastructure elevates the importance of timely remediation.

Summary

CVE-2026-1973 identifies a null pointer dereference vulnerability in the Free5GC 5G core network software, specifically within the Session Management Function (SMF) component's establishPfcpSession function. This function is responsible for establishing PFCP (Packet Forwarding Control Protocol) sessions, which are critical for managing user plane resources in 5G networks. The vulnerability arises when crafted input causes the function to dereference a null pointer, leading to a crash or denial of service (DoS) condition. The flaw can be triggered remotely over the network without requiring authentication or user interaction, making it accessible to unauthenticated attackers. The CVSS 4.0 base score is 6.9 (medium severity), reflecting the ease of exploitation and the impact on availability, but no direct compromise of confidentiality or integrity. Although no active exploits have been reported in the wild, the public disclosure increases the likelihood of exploitation attempts. Free5GC is an open-source 5G core network implementation used by telecom operators and research institutions globally, making this vulnerability relevant to critical 5G infrastructure. The absence of patches at the time of disclosure necessitates immediate attention to mitigate potential service disruptions.

References

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