VulnerabilityPublished 29 Jan 2026Updated 23 Feb 2026

CVE-2026-1587: Open5GS · Denial of Service

Affects Open5GSSource CVE Database V5

Public exploit available · CVSS 6.9 Medium.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 4.0 base score

6.9Medium

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

EPSS: 0.5% 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 29 Jan 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–
GitHubopen5gs/open5gs`pkg:github/open5gs/open5gs`Other threats	Affected 2.7.0 – 2.7.6 7 affected builds	Fixed in–

CPE configurations (1)

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

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AI-suggested

To mitigate CVE-2026-1587, organizations should promptly apply the official patches or upgrade Open5GS to versions later than 2.7.6 where the vulnerability is fixed. Network operators should implement strict filtering and validation of S11 interface traffic to block malformed or suspicious Modify Bearer Request messages. Deploying intrusion detection/prevention systems (IDS/IPS) with signatures tuned to detect anomalous S11 traffic patterns can help identify exploitation attempts. Limiting network exposure of the S11 interface to trusted entities and enforcing network segmentation reduces the attack surface. Monitoring SGWC process health and implementing automated failover or restart mechanisms can minimize downtime if an attack occurs. Regularly auditing and updating Open5GS deployments, combined with comprehensive logging and alerting on control plane anomalies, will enhance early detection and response capabilities. Finally, organizations should stay informed about updates from Open5GS maintainers and security advisories related to 5G core components.

Description

A vulnerability has been found in Open5GS up to 2.7.6. The affected element is the function sgwc_s11_handle_modify_bearer_request of the file /sgwc/s11-handler.c of the component SGWC. The manipulation leads to denial of service. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used. Applying a patch is the recommended action to fix this issue. The issue report is flagged as already-fixed.

Impact

Exploitation of CVE-2026-1587 can cause denial of service in the SGWC component of Open5GS, leading to service outages or degraded performance in 5G core network operations. This disruption can affect bearer management, impacting user data sessions and potentially causing dropped connections or inability to establish new sessions. For mobile network operators and enterprises relying on Open5GS for 5G core functions, this could translate into network downtime, customer dissatisfaction, and potential financial losses. The lack of authentication or user interaction requirements increases the risk of automated or widespread attacks. While the vulnerability does not compromise data confidentiality or integrity, the availability impact on critical network infrastructure is significant. The absence of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as the exploit code is publicly available. Organizations running vulnerable Open5GS versions should consider the potential for targeted attacks aiming to disrupt service availability.

References

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