Tillitis TKey Client has an Error in Protocol Implementation

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

4.7 · CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:H/SI:H/SA:H · score source

EPSS

• CVE-2026-32953: 0.25% estimated exploitation activity in the next 30 days; percentile 16.44 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Some specific (1 out of 256) User Supplied Secrets (USS) were not used, making the resulting Compound Device Identifier (CDI) the same as if no USS was provided. Affected client applications: all client apps using the tkeyclient Go module. Patches Upgrade to v1.3.0. NOTE WELL: For the affected end users upgrading an app containing tkeyclient to v1.3.0 means their key material will change. An end user can get their old keys by not entering any USS. Please make sure to communicate this to end users. Affected users The steps required to assess whether your USS is vulnerable may vary depending on the client application. The example below shows how to perform the check using tkey-ssh-agent and the known vulnerable USS adl. 1. Insert the TKey into the client 2. Run tkey-ssh-agent -p --uss 3. When prompted for a User Supplied Secret, enter adl 4. Note the public key and call it pubkey-with-uss 5. Remove the TKey from the client 6. Insert the TKey into the client again 7. Run…

Published by the source

17 Mar 2026, 19:42 UTC

Last modified by the source

20 Mar 2026, 21:22 UTC

Source last checked

26 Oct 2026, 15:18 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-4w7r-3222-8h6v

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# Patch Next advisory brief: CVE-2026-32953

Advisory: Tillitis TKey Client has an Error in Protocol Implementation
IDs: CVE-2026-32953, GHSA-4w7r-3222-8h6v
Record: https://patchnext.com/advisories/cve-2026-32953 (revision 1, source checked 26 Oct 2026, 15:18 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/tillitis/tkeyclient 1.3.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/tillitis/tkeyclient: affected < 1.3.0; fixed in 1.3.0

## Suggested inspection (read-only)
- Go github.com/tillitis/tkeyclient: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/tillitis/tkeyclient.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-4w7r-3222-8h6v (GitHub-reviewed advisory GHSA-4w7r-3222-8h6v lists affected ranges: Go github.com/tillitis/tkeyclient >=0 <1.3.0)

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