Cyber Resilience

CVE-2025-25565

Memory Safety in Softether Vpn 5.02.5187

Public PoCMemory Safety
Published
12 March 2025
Modified
19 July 2025
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0061 46th percentile
Risk Priority 72 floored blend · peak EPSS

Summary

CVE-2025-25565 is a critical-severity Classic Buffer Overflow (CWE-120) vulnerability in Softether Vpn. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 46th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2025-25565 is a buffer overflow vulnerability (CWE-120) affecting SoftEther VPN version 5.02.5187, specifically in the Command.c source file through the PtMakeCert and PtMakeCert2048 functions. Published on 2025-03-12, it has been assigned a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical severity with potential for high impacts on confidentiality, integrity, and availability.

The vulnerability can be triggered by providing overly long input strings to the affected functions, leading to a buffer overflow. While the CVSS vector suggests network-accessible exploitation without privileges or user interaction, the supplier disputes its validity as a remotely exploitable issue, asserting that it only enables a local user to attack themselves by entering a long string directly on the command line.

Advisories referenced in the CVE include a supplier statement at https://filecenter.softether-upload.com/d/250715_001_79538/CVE-2025-25565.pdf and researcher details at https://lzydry.github.io/CVE-2025-25565/, which highlight the disputed self-affecting nature but do not specify patches or mitigations beyond the supplier's position that it does not qualify as a vulnerability warranting fixes.

EU & UK References

Vulnerability Data

SoftEther VPN 5.02.5187 is vulnerable to Buffer Overflow in the Command.c file via the PtMakeCert and PtMakeCert2048 functions. NOTE: the Supplier disputes this because the behavior only allows a user to attack himself by typing a long string on a…

more

command line.

CWE(s)
CWE-120

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-25567Same product: Softether Vpn
CVE-2025-25568Same product: Softether Vpn
CVE-2023-22308Same product: Softether Vpn
CVE-2023-23581Same product: Softether Vpn
CVE-2023-27395Same product: Softether Vpn
CVE-2023-31192Same product: Softether Vpn
CVE-2023-27516Same product: Softether Vpn
CVE-2023-22325Same product: Softether Vpn
CVE-2023-32275Same product: Softether Vpn
CVE-2023-25774Same product: Softether Vpn

Affected Assets

softether
vpn
5.02.5187

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V5.2.1

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and analysis can find missing size checks before deployment.

SI-10 Information Input Validation good match

Input validation directly enforces size checks before buffer copies.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles require bounds checking and safe buffer handling in design.

SI-16 Memory Protection partial match

Memory protection limits the impact of an overflow once it occurs.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure development practices directly enforce bounds checking and input validation that prevent classic buffer overflows.

ID.RA-01 partial match
prevents

Vulnerability identification processes such as code review or scanning detect classic buffer overflows before exploitation.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing unchecked buffer copies with corrected versions.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.28 Secure coding mostly match
prevents

Secure coding directly requires bounds-checked memory operations, addressing the root cause of CWE-120.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development and acceptance can detect buffer overflows through fuzzing and static analysis, though it does not prevent them at the source.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates processes that can include input validation and bounds checking to prevent buffer overflows.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify input-size validation and safe buffer handling to mitigate classic buffer overflows.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure system architecture and engineering principles promote defensive coding patterns that reduce the likelihood of unchecked buffer copies.

References