CVE
C-Kermit authentication bypass in IKSD certificate login
Affects C-Kermit 7.0.197 before 11.1.515 when built with SSL/TLS support and IKSD accepts login by client certificate. Fixed in 11.1.515.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 11.1.515
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. C-Kermit is built with SSL/TLS support IKSD is configured to accept login by client certificate The client certificate verification fails and IKSD then prompts for a login
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 16/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
C-Kermit, from OpenKermit, is affected by an authentication bypass in its IKSD SSL build. An attacker who holds a trusted certificate mapped to a refused account can remotely log in as any other account with any password and gain that account's shell access, and the attack needs low-privilege login over the network.
Read the original description
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.
Who should check
Teams running C-Kermit 7.0.197 through 11.1.515 as an IKSD server with an SSL/TLS build that accepts client certificate logins, or as a telnet-over-TLS client.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure8/25Specific setups only, reachable over the network
- Reach?/20Unknown. No tracked technology or package matched
- Severity7.7/10CVSS 7.7
- No patch0/5No signal
What would change the score
- Would score about 66 if added to CISA KEV
- Would score about 61 if CISA's SSVC rates exploitation active
- Would score about 23 if CISA's SSVC rates it automatable
What to do
Check whether your setup matches what the bug needs.
C-Kermit is built with SSL/TLS support IKSD is configured to accept login by client certificate The client certificate verification fails and IKSD then prompts for a loginUpgrade to a fixed version: 11.1.515.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-129116 (C-Kermit 7.0.197 before 11.1.515 IKSD Authentication Bypass via Refused Certificate Login), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-129116 (entry last updated 2026-11-13):
Affected:
- OpenKermit C-Kermit: from 7.0.197, fixed in 11.1.515
Fixed versions: 11.1.515.
Conditions (all must be true for the bug to be hit):
- C-Kermit is built with SSL/TLS support (source: https://github.com/OpenKermit/ckermit/security/advisories/GHSA-5pc4-gh6q-5h4w)
- IKSD is configured to accept login by client certificate (source: https://github.com/OpenKermit/ckermit/security/advisories/GHSA-5pc4-gh6q-5h4w)
- The client certificate verification fails and IKSD then prompts for a login (source: https://github.com/OpenKermit/ckermit/security/advisories/GHSA-5pc4-gh6q-5h4w)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, low-privilege login, no user action.
CISA KEV: CVE-2026-129116 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-129116 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/OpenKermit/ckermit/security/advisories/GHSA-5pc4-gh6q-5h4w
- https://github.com/OpenKermit/ckermit/commit/fdfe8f13159f9276d87e02bedba15946b0edda97
- https://github.com/OpenKermit/ckermit/releases/tag/v11.1.515
- https://github.com/OpenKermit/ckermit/blob/v11.0.514/ckufio.c#L8249
- https://www.vulncheck.com/advisories/c-kermit-7.0.197-before-11.1.515-iksd-authentication-bypass-via-refused-certificate-login
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-129116
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-129116"}.Timeline
- CVE published
- First seen by cve.now
Affected versions
- OpenKermit C-Kermit
From 7.0.197 · fixed in 11.1.515
Evidence 6
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-129116
Is CVE-2026-129116 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: cve.now feed data
What does this mean?
When IKSD is run with client certificate login and certificate verification fails, IKSD prompts for a login instead of rejecting the connection. The flaw lets a login succeed as another user with any password, giving that account's shell access.Source: github.com
Which versions are affected by CVE-2026-129116?
C-Kermit: from 7.0.197 before 11.1.515.Source: cve.now feed data
Am I affected, and how do I check?
Versions from 7.0.197 up to but not including 11.1.515 are in the affected range. The setup must be built with SSL/TLS support and have IKSD configured to accept login by client certificate. Check the C-Kermit version and whether the build and IKSD configuration match these conditions.Source: github.com
How do I fix CVE-2026-129116?
Upgrade C-Kermit to 11.1.515 or later, which is the fixed version listed for this vulnerability.Source: github.com