VulnerabilityPublished 12 Mar 2025Updated 19 Jul 2025

CVE-2025-25568: SoftEtherVPN · Use After Free

Source CVE Database V5

Not known to be exploited · CVSS 9.8 Critical.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

9.8Critical

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 47% 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:H/I:H/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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 12 Mar 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

Inventory and Audit: Identify all instances of SoftEtherVPN and any associated stress-testing tools deployed within the organization. Confirm whether the vulnerable stress-testing tool is in use.
Restrict Access: Limit network exposure of the stress-testing tool to trusted internal networks only, preventing external or untrusted access.
Privilege Management: Ensure that the stress-testing tool runs with the least privileges necessary, ideally under non-administrative user accounts, to reduce impact if exploited.
Monitor for Updates: Maintain close monitoring of SoftEtherVPN vendor advisories and CVE databases for patches or official guidance addressing this vulnerability.
Disable or Remove: If the stress-testing tool is not essential, disable or uninstall it to eliminate the attack surface.
Network Segmentation: Isolate systems running the stress-testing tool from critical infrastructure to contain potential exploitation.
Logging and Detection: Enhance logging around the use of the stress-testing tool and monitor for anomalous behavior that could indicate exploitation attempts.
Incident Response Preparedness: Prepare response plans for potential exploitation scenarios, including forensic readiness and containment strategies.

Description

SoftEtherVPN 5.02.5187 is vulnerable to Use after Free in the Command.c file via the CheckNetworkAcceptThread function. NOTE: the Supplier disputes this because the use-after-free is not in the VPN software, but is instead in a separate tool that has no untrusted input and runs under the user's own privileges (it is a stress-testing tool for a networking stack).

Impact

For European organizations, the impact of CVE-2025-25568 depends heavily on whether the vulnerable stress-testing tool is deployed in their environments. If the tool is not used or is isolated from untrusted inputs, the risk is minimal. However, if organizations employ this tool for network stack testing, the vulnerability could allow remote attackers to execute arbitrary code, leading to full compromise of affected systems. This could result in data breaches, disruption of VPN services, and potential lateral movement within networks. Given SoftEtherVPN's use in various sectors including government, finance, and healthcare across Europe, exploitation could undermine secure remote access infrastructure, impacting confidentiality and availability of critical communications. The critical severity and network-level exploitability without authentication mean that vulnerable systems exposed to the internet could be targeted by attackers to gain unauthorized access or disrupt services. The supplier's note that the vulnerable component runs with user privileges and does not accept untrusted input somewhat mitigates the risk, but organizations should not dismiss the threat, especially in environments where the stress-testing tool is used or where custom configurations might expose the vulnerability.

CWE-416Use After Free (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #7
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Architecture and Design · Language Selection
Choose a language that provides automatic memory management.
Implementation · Attack Surface Reduction
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 19 Jul 2025, 20:33 UTC

WeaknessesCWE-416

Technical details

References

Community reviews

Related threats