---
id: "CVE-2026-129116"
page: "https://infrastack.ai/live/CVE-2026-129116"
kind: "vulnerability"
aliases: ["CVE-2026-129116"]
title: "C-Kermit: IKSD SSL build lets refused certificate logins bypass authentication"
severity: "high"
cvss: 7.7
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["c-kermit", "iksd", "runtime", "self-hosted", "telnet"]
not_affected_if: ["certificate-login-disabled", "iksd-not-running", "no-ssl-build"]
published_at: "2026-11-13T17:17:28+00:00"
first_seen_at: "2026-11-13T17:48:00+00:00"
updated_at: "2026-11-13T17:48:50+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-129116", "first_seen_at": "2026-11-13T17:48:00+00:00"}]
exploit_sources: []
---

# C-Kermit: IKSD SSL build lets refused certificate logins bypass authentication

Link for people: https://infrastack.ai/live/CVE-2026-129116 (this .md is for agents)

C-Kermit's IKSD server in its SSL build leaves Telnet authentication marked valid after a certificate login is refused. An attacker holding a trusted certificate mapped to a refused account can log in as any other account with any password and get that account's shell.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed C-Kermit version with `kermit -v` or the package manager; affected range is `7.0.197` before `11.1.515`.
- Check whether IKSD is running with SSL enabled and whether it accepts certificate logins (unknown for default config).

## Fix

- C-Kermit: move to `11.1.515` or later (per the product ranges).

## Timeline

- 2026-11-13T17:48:00+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-129116

## Documents

- [advisory] Vendor advisory: github.com https://github.com/OpenKermit/ckermit/security/advisories/GHSA-5pc4-gh6q-5h4w
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/c-kermit-7.0.197-before-11.1.515-iksd-authentication-bypass-via-refused-certificate-login
- [fix] Patch: github.com https://github.com/OpenKermit/ckermit/commit/fdfe8f13159f9276d87e02bedba15946b0edda97
- [fix] Release notes: github.com https://github.com/OpenKermit/ckermit/releases/tag/v11.1.515

## From the sources

C-Kermit from 7.0.197 before 11.1.515 contains an authentication bypass vulnerability in the IKSD SSL build that leaves Telnet authentication state at AUTH_VALID after a refused certificate login. Attackers holding a trusted certificate mapped to a refused account can log in as any other account with any password, gaining that account's shell access.

---

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