Cyber Resilience

CVE-2025-70034

Mscdex Ssh2 1.17.0

Published
09 March 2026
Modified
06 May 2026
Patch / advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0034 27th percentile
Risk Priority 57 floored blend · peak EPSS

Summary

CVE-2025-70034 is a high-severity Inefficient Regular Expression Complexity (CWE-1333) vulnerability in Mscdex Ssh2. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 27th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — 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-2025-70034 is a vulnerability classified under CWE-1333 (Inefficient Regular Expression Complexity, also known as ReDoS) affecting version 1.17.0 of the mscdex ssh2 library. Published on 2026-03-09, it carries a CVSS v3.1 base score of 7.5 (High), reflecting its potential for significant impact despite no effects on confidentiality or integrity.

The vulnerability enables remote, unauthenticated attackers to exploit it over the network with low attack complexity and no user interaction required. Successful exploitation results in high-impact denial of service, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), potentially causing resource exhaustion through malicious inputs that trigger excessive computation in regular expression processing.

References include a GitHub Gist at https://gist.github.com/zcxlighthouse/78a0d9b7fcae20294076e8b24f763ce5 detailing the issue, along with the mscdex organization page (https://github.com/mscdex) and the ssh2 repository (https://github.com/mscdex/ssh2), which security practitioners should review for any advisories, patches, or mitigation guidance specific to affected deployments.

EU & UK References

Vulnerability Data

An issue pertaining to CWE-1333: Inefficient Regular Expression Complexity (4.19) was discovered in mscdex ssh2 v1.17.0.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-6688Shared CWE-1333
CVE-2023-45813Shared CWE-1333
CVE-2026-57584Shared CWE-1333
CVE-2025-2937Shared CWE-1333
CVE-2025-27220Shared CWE-1333
CVE-2023-25167Shared CWE-1333
CVE-2026-4923Shared CWE-1333
CVE-2024-45338Shared CWE-1333
CVE-2025-70030Shared CWE-1333
CVE-2026-16270Shared CWE-1333

Affected Assets

mscdex
ssh2
1.17.0

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can discover inefficient regex patterns via performance or static analysis.

Development standards and tools can require safe regex construction and forbid known exponential patterns.

Denial-of-service protections limit resource exhaustion caused by expensive regex evaluation.

Input validation can constrain data that would otherwise trigger worst-case regex complexity.

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 SDLC practices directly prevent inefficient regex via reviews, static analysis, and safe libraries.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover ReDoS issues in existing code but do not stop their introduction.

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.

finds

Security testing can detect and reject regex patterns with exponential worst-case complexity.

prevents

Secure development lifecycle mandates review of algorithmic efficiency, directly addressing ReDoS-prone regex.

prevents

Application security requirements can specify input-validation rules that limit regex complexity.

prevents

Secure architecture principles encourage avoidance of computationally expensive constructs such as catastrophic backtracking.

prevents

Secure coding standards explicitly prohibit or limit the use of inefficient regular expressions.

References