CVE-2025-15539VulnerabilityPublished 18 Jan 2026Updated 23 Feb 2026

CVE-2025-15539: Open5GS · Denial of Service

Affects Open5GSSource 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: 0.7% chance of exploitation in 30 days – higher than 54% 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 18 Jan 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
Open5GS	Affected =2.7.0 =2.7.1 =2.7.2 =2.7.3 =2.7.4 =2.7.5 =2.7.6	Fixed in–
GitHubopen5gs/open5gs`pkg:github/open5gs/open5gs`Other threats	Affected =2.7.0 =2.7.1 =2.7.2 =2.7.3 =2.7.4 =2.7.5 =2.7.6	Fixed in–

CPE configurations (1)

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

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AI-suggested

To mitigate CVE-2025-15539, organizations should immediately apply the official patch provided by the Open5GS project, identified by commit b4707272c1caf6a7d4dca905694ea55557a0545f, or upgrade to a fixed version beyond 2.7.6. Network segmentation should be enforced to restrict access to the SGWC S11 interface, limiting exposure to untrusted networks and reducing the attack surface. Deploying intrusion detection and prevention systems (IDS/IPS) with signatures tuned to detect anomalous or malformed S11 messages can help identify and block exploitation attempts. Monitoring logs and network traffic for unusual patterns related to downlink data notification acknowledgments is recommended. Operators should implement rate limiting on control plane interfaces to mitigate potential flooding attacks. Regular vulnerability scanning and penetration testing of the 5G core network components can help identify residual risks. Finally, maintaining an up-to-date inventory of Open5GS deployments and ensuring timely patch management processes are critical to reduce exposure to this and future vulnerabilities.

Description

A vulnerability was determined in Open5GS up to 2.7.6. Impacted is the function sgwc_s11_handle_downlink_data_notification_ack of the file src/sgwc/s11-handler.c of the component sgwc. This manipulation causes denial of service. The attack can be initiated remotely. The exploit has been publicly disclosed and may be utilized. Patch name: b4707272c1caf6a7d4dca905694ea55557a0545f. To fix this issue, it is recommended to deploy a patch. The issue report is flagged as already-fixed.

Impact

The primary impact of CVE-2025-15539 is denial of service, which affects the availability of the Open5GS 5G core network component. Disruption of the SGWC function can lead to interruption of critical 5G core network services, including session management and data forwarding for mobile subscribers. This can result in degraded network performance, dropped connections, and service outages for end users relying on the affected network. Telecom operators and service providers using Open5GS in production environments may experience partial or full service disruption, impacting customer experience and potentially causing financial and reputational damage. Given the role of Open5GS in 5G infrastructure, this vulnerability could also affect IoT services, enterprise connectivity, and public safety communications that depend on stable 5G networks. Although the vulnerability does not impact confidentiality or integrity, the availability impact is significant for network operators. The ease of remote exploitation without authentication increases the threat level, especially in environments where the vulnerable component is exposed to untrusted networks.

References

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