Vulnerability · Published Mar 20, 2026 · Assigned by GitHub_M
CVE-2026-32953Tillitis: TKey Client has an Error in Protocol Implementation
Medium 4.7
In plain English
A medium-severity security flaw in tkeyclient from tillitis. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:13 | golang-github-tillitis-tkeyclient | no fix listed | DEBIAN-CVE-2026-32953 |
| Debian:14 | golang-github-tillitis-tkeyclient | 1.3.0-1 | DEBIAN-CVE-2026-32953 |
| Go | github.com/tillitis/tkeyclient | 1.3.0 | GO-2026-4728 |
| Go | github.com/tillitis/tkeyclient | 1.3.0 | GHSA-4w7r-3222-8h6v |
| Ubuntu:25.10 | golang-github-tillitis-tkeyclient | no fix listed | UBUNTU-CVE-2026-32953 |
| Ubuntu:26.04:LTS | golang-github-tillitis-tkeyclient | no fix listed | UBUNTU-CVE-2026-32953 |
| Ubuntu:26.10 | golang-github-tillitis-tkeyclient | no fix listed | UBUNTU-CVE-2026-32953 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| tillitis | tkeyclient | < 1.3.0 |
Weakness: CWE-303 · Vector: 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