VulnerabilityPublished 15 Feb 2026Updated 23 Feb 2026

CVE-2026-2521: Open5GS · Memory Corruption

Affects Open5GSSource CVE Database V5

Public exploit available · CVSS 6.9 Medium.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 4.0 base score

6.9Medium

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

EPSS: 0.7% chance of exploitation in 30 days – higher than 55% 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 15 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CVSS exploit maturity: proof of concept public
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), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

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 or the CVSS exploit maturity 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
Open5GS	Affected 2.7.0 – 2.7.6 7 affected builds	Fixed in–

CPE configurations (1)

cpe:2.3:a:open5gs:open5gs:*:*:*:*:*:*:*:*

AI-suggested

Immediate mitigation should focus on network-level protections such as firewall rules and access control lists to restrict access to the SGW-C S5-C interface from untrusted networks, limiting exposure to potential attackers.
Deploy intrusion detection and prevention systems (IDS/IPS) with signatures or heuristics to detect anomalous or malformed session creation response messages targeting the vulnerable function.
Monitor network logs and traffic for unusual patterns or crashes related to the SGW-C component to identify exploitation attempts early.
Engage with the Open5GS community and maintain awareness of updates or patches addressing this vulnerability; apply official patches promptly once released.
Consider deploying application-layer mitigations such as input validation or sandboxing around the affected function if feasible within the Open5GS codebase.
For operators running Open5GS in production, plan for rapid incident response and recovery procedures to minimize downtime in case of exploitation.
Evaluate alternative 5G core implementations or vendor-supported solutions with active security maintenance if patching is delayed.
Conduct regular security assessments and penetration testing focusing on 5G core network components to identify and remediate similar vulnerabilities proactively.

Description

A weakness has been identified in Open5GS up to 2.7.6. This issue affects the function sgwc_s5c_handle_create_session_response of the component SGW-C. Executing a manipulation can lead to memory corruption. The attack may be performed from remote. The exploit has been made available to the public and could be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Impact

The vulnerability impacts the core network infrastructure of 5G deployments using Open5GS, specifically the Serving Gateway Control Plane responsible for session management. Exploitation can lead to memory corruption, which may cause service disruption through crashes or denial of service, impacting network availability. In worst cases, attackers might achieve arbitrary code execution, threatening the integrity and confidentiality of network functions and user data. Given that Open5GS is used globally in both production and research environments, the threat could affect telecom operators, private 5G networks, and enterprises deploying Open5GS-based solutions. Disruption of 5G core network components can degrade service quality, interrupt subscriber connectivity, and potentially expose sensitive subscriber information. The availability of public exploit code lowers the barrier for attackers, increasing the likelihood of targeted attacks. The absence of authentication and user interaction requirements further broadens the attack surface. Overall, this vulnerability poses a significant risk to the stability and security of 5G networks relying on Open5GS, with potential cascading effects on dependent services and applications.

References

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