CVE-2026-21444Public exploit

Confidentiality loss via discarded updated initialization vector

Published Jan 2, 2026 · Updated Jan 2, 2026

Cryptographic IV handling in Stefan Berger libtpms 0.10.0 through 0.10.1 allows local users to weaken data confidentiality. In src/tpm2/crypto/openssl/Helpers.c, DoEVPGetIV uses OSSL_PARAM_octet_ptr, which allocates an updated-IV buffer that never reaches the caller and leaves the initial IV in use. Exploitation requires low-privileged local access to a TPM 2 integration built with OpenSSL 3.x and affects subsequent chained encryption or decryption.

CVSS severity5.5
Medium
EPSS probability0.08%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cryptographic IV handling in Stefan Berger libtpms 0.10.0 through 0.10.1 allows local users to weaken data confidentiality. In src/tpm2/crypto/openssl/Helpers.c, DoEVPGetIV uses OSSL_PARAM_octet_ptr, which allocates an updated-IV buffer that never reaches the caller and leaves the initial IV in use. Exploitation requires low-privileged local access to a TPM 2 integration built with OpenSSL 3.x and affects subsequent chained encryption or decryption.

The record

CVE
CVE-2026-21444
Published
Jan 2, 2026
Updated
Jan 2, 2026
Vendor
libtpms Project
Product
libtpms
Classifications
CWE-327, CWE-330
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 0.10.0, < 0.10.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

libtpms Project · libtpmsversion=>= 0.10.0, < 0.10.2

Published CVSS scores

5.5GitHubCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm
CWE-330Use of Insufficiently Random Values

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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