VulnerabilityPublished 18 Dec 2025Updated 19 Dec 2025

CVE-2025-65559: Open5GS · Reachable Assertion

Source CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Dec 2025
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 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

AI-suggested

Immediate mitigation involves implementing strict validation of PFCP Session Establishment Requests, specifically verifying that the F-TEID address-family flags align with the configured GTP-U resource family for the selected DNN before processing.
Network operators should deploy network-level filtering or rate limiting on PFCP traffic to the UPF to reduce exposure to malformed or malicious packets.
Monitor UPF logs and system health metrics for signs of assertion failures or crashes related to PFCP processing.
Engage with the Open5GS community or vendors for patches or updated releases addressing this vulnerability and plan prompt deployment once available.
Consider deploying redundant UPF instances and failover mechanisms to minimize service disruption in case of crashes.
Conduct thorough testing of PFCP message handling in staging environments to detect similar protocol parsing issues.
Review and update security policies to include anomaly detection for unusual PFCP traffic patterns.
Educate network operations teams about this specific vulnerability and response procedures to reduce incident response times.

Description

An issue was discovered in Open5GS 2.7.5-49-g465e90f, when processing a PFCP Session Establishment Request (type=50), the UPF crashes with a reachable assertion in `lib/pfcp/context.c` (`ogs_pfcp_object_teid_hash_set`) if the CreatePDR?PDI?F-TEID has CH=1 and the F-TEID address-family flag(s) (IPv4/IPv6) do not match the GTP-U resource family configured for the selected DNN (Network Instance), resulting in a denial of service.

Impact

For European organizations, particularly telecom operators and 5G service providers deploying Open5GS as part of their 5G core network infrastructure, this vulnerability poses a significant risk to network availability. A successful exploit can crash the UPF, a critical component responsible for forwarding user plane traffic, leading to service disruptions affecting end-users and enterprise customers. This can result in degraded network performance, dropped sessions, and potential revenue loss. Additionally, denial of service conditions in core network elements can cascade, impacting other dependent network functions and services. Given the increasing reliance on 5G for critical communications, IoT, and industrial applications in Europe, such outages could have broader economic and operational consequences. The vulnerability does not compromise confidentiality or integrity but undermines trust in network reliability. Organizations operating multi-vendor or open-source 5G core stacks must prioritize identifying vulnerable UPF instances and implement mitigations to maintain service continuity.

CWE-617Reachable Assertion (opens in a new tab)
Base weakness
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
Implementation
Make sensitive open/close operation non reachable by directly user-controlled data (e.g. open/close resources)
Implementation · Input Validation
Perform input validation on user data.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/open5gs/open5gs/issues/4135 (opens in a new tab)

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 25 Dec 2025, 19:55 UTC

WeaknessesCWE-617

Technical details

References

Community reviews

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