CVE-2026-1976VulnerabilityPublished 6 Feb 2026Updated 23 Feb 2026

CVE-2026-1976: Free5GC · NULL Pointer Dereference

Affects Free5GCSource CVE Database V5

Not known to be exploited · CVSS 6.9 Medium.

Data as of 25 Oct 2026, 19:02 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 2026-10-25.

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:*:*:*:*:*:*:*:*

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2026-1976, organizations should: 1) Monitor official Free5GC project repositories and security advisories for the release of patches addressing this vulnerability and apply them promptly. 2) Implement network-level protections such as firewall rules and intrusion detection/prevention systems (IDS/IPS) to restrict access to the SMF component from untrusted networks, limiting exposure to potential attackers. 3) Employ network segmentation to isolate critical 5G core components, reducing the attack surface. 4) Conduct regular security assessments and penetration testing focused on 5G core infrastructure to identify and remediate similar vulnerabilities proactively. 5) Maintain up-to-date incident response plans tailored to telecom network disruptions to minimize downtime in case of exploitation. 6) Consider deploying runtime application self-protection (RASP) or behavior monitoring tools on SMF instances to detect abnormal crashes or exploitation attempts. 7) Engage with the Free5GC community and vendors for timely intelligence sharing and coordinated vulnerability management.

Description

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 to the public and could be used for attacks. It is suggested to install a patch to address this issue.

Impact

The primary impact of CVE-2026-1976 is denial of service against the SMF component of Free5GC, which is a vital part of 5G core network infrastructure. Disruption of SMF services can lead to session management failures, affecting subscriber connectivity and network stability. For telecom operators, this can translate into degraded service quality, dropped connections, and potential revenue loss. The vulnerability does not directly compromise data confidentiality or integrity but undermines network availability, which is critical for 5G services supporting IoT, critical communications, and enterprise applications. The ease of remote exploitation without authentication increases the risk of widespread attacks, especially as 5G networks expand globally. Organizations relying on Free5GC for 5G core functions must consider the operational impact of potential outages and the reputational damage from service interruptions. The availability of a public exploit further elevates the threat landscape, necessitating immediate attention.

References

Community reviews

Loading reviews…