What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-01-02 · updated 2026-06-17
• Weakness: CWE-327

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.

Affected products

• stefanberger libtpms: from 0.10.0 before 0.10.2 — fixed in 0.10.2

How to fix

Upgrade to a fixed version: stefanberger libtpms 0.10.2. Check the vendor advisory for mitigations.

References

• https://github.com/stefanberger/libtpms/commit/33c9ff074cb16c1841ce7d7f33643c17c426743a
• https://github.com/stefanberger/libtpms/issues/541
• https://github.com/stefanberger/libtpms/security/advisories/GHSA-7jxr-4j3g-p34f

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