CVE-2026-32953 Tillitis: TKey Client has an Error in Protocol Implementation
A bug in the TKey client library causes certain user-supplied secrets to be ignored, resulting in predictable key material and weakened security.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-32953?
CVE-2026-32953 is a medium-severity vulnerability in tillitis tkeyclient, published on 20 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Tillitis TKey Client package is a Go package for a TKey client. Versions 1.2.0 and below contain a critical bug in the tkeyclient Go module which causes 1 out of every 256 User Supplied Secrets (USS) to be silently ignored, producing the same Compound Device Identifier (CDI)—and thus the same key material—as if no USS is provided. This happens because a buffer index error overwrites the USS-enabled boolean with the first byte of the USS digest, so any USS whose hash starts with 0x00 is effectively discarded. This issue has been fixed in version 1.3.0. Users unable to upgrade immediately should switch to a USS whose hash does not begin with a zero byte.
Weakness: CWE-303
Which versions are affected by CVE-2026-32953?
3 open source packages ship an affected version, including github.com/tillitis/tkeyclient. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/tillitis/tkeyclient Go | All versions | 1.3.0 |
github.com/tillitis/tkeyclient Go | All versions | 1.3.0 |
github.com/tillitis/tkeyclient Go | All versions | 1.3.0 |
Products include Tillitis Tkey Client.
How do I fix CVE-2026-32953?
Upgrade github.com/tillitis/tkeyclient to 1.3.0 or later.
Is CVE-2026-32953 being exploited?
There is no known exploitation of CVE-2026-32953 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-32953, GHSA-4w7r-3222-8h6v, GO-2026-4728, UBUNTU-CVE-2026-32953.