CVE-2026-21444: libtpms returns wrong initialization vector when certain symmetric ciphers are used

Vulnerability summary

CVE-2026-21444 is a medium (CVSS 5.5) vulnerability in libtpms_project libtpms. EPSS estimates a 0.08% chance of exploitation in the next 30 days, higher than 0.1% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 02-01-2026
   PublishedVulnerability first disclosed.
2. 05-01-2026
   Last modifiedVulnerability information updated.

Description

libtpms, a library that provides software emulation of a Trusted Platform Module, has a flaw in versions 0.10.0 and 0.10.1. The commonly used integration of libtpms with OpenSSL 3.x contained a vulnerability related to the returned IV (initialization vector) when certain symmetric ciphers were used. Instead of returning the last IV it returned the initial IV to the caller, thus weakening the subsequent encryption and decryption steps. The highest threat from this vulnerability is to data confidentiality. Version 0.10.2 fixes the issue. No known workarounds are available.

• CWE-327Use of a Broken or Risky Cryptographic AlgorithmThe product uses a broken or risky cryptographic algorithm or protocol.
• CWE-330Use of Insufficiently Random ValuesThe product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.