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Libtpms CVE-2026-21444

MEDIUM
Use of a Broken or Risky Cryptographic Algorithm (CWE-327)
2026-01-02 security-advisories@github.com
TLS OpenSSL Red Hat Libtpms Suse Libtpms Project
5.5
CVSS 3.1 · GitHub Advisory
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Vulnerability Assessment

Weakness
CWE
CWE-327
OWASP Top 10:2025
A04:2025 - Cryptographic Failures
ASVS 5.0
V11 - Cryptography Approved algorithm selection
Impact

CVSS 5.5 (MEDIUM). Attack vector: Local. Complexity: Low. Privileges required: Low. User interaction: None. Public exploit/POC available.
Exploit ScenarioDerived

An attacker could exploit this vulnerability to compromise the affected system.
This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Improper IV handling in libtpms 0.10.0 and 0.10.1 causes the library to return initial instead of final initialization vectors during symmetric cipher operations with OpenSSL 3.x, potentially weakening cryptographic security for local users who can interact with the TPM emulation. Public exploit code exists for this vulnerability affecting confidentiality of encrypted data. Update to libtpms 0.10.2 to remediate.

Earlier versions of this analysis (1)
v1 Mar 12, 2026 - 21:54 CVSS 5.5

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. [CVSS 5.5 MEDIUM]

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Technical ContextAI · show details

Classified as CWE-327 (Use of a Broken or Risky Cryptographic Algorithm). Affects Libtpms. 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 confide

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Severity by source

GitHub Advisory PRIMARY 5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
SUSE MEDIUM
Red Hat 6.5 MEDIUM

Primary rating from GitHub Advisory.

CVSS VectorGitHub Advisory

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

Lifecycle Timeline

3
PoC Detected
Feb 25, 2026 - 15:18 vuln.today
Public exploit code
Patch released
Feb 25, 2026 - 15:18 nvd
Patch available
CVE Published
Jan 02, 2026 - 19:15 nvd
MEDIUM 5.5

DescriptionGitHub Advisory

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.

Executive ViewAI

Why It Matters

CVE-2026-21444 presents moderate security risk, a broken cryptography vulnerability rated CVSS 5.5. Exploitation could compromise the security of affected deployments. Proof-of-concept code is publicly available. A patch is available and should be applied during regular vulnerability management.

Business Impact: Low
Compensating Controls

Apply vendor patch. If patching is delayed: enforce TLS 1.2+ and disable weak cipher suites.

Threat Intelligence Overview

EPSS Score
0.0%
Top 100% exploitable
Exploit
POC
Public exploit code exists
Data Quality
4 sources
Confidence: Medium
NVD CVE.org EPSS Vendor GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC Yes
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation· derived
Poc
System Exposure· derived
Small
Automatable· derived
No
Human Impact
Low

Priority Score

48
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +28
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Affected Products (CPE)GitHub Advisory

cpe:2.3:a:libtpms_project:libtpms:*:*:*:*:*:*:*:*

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Same weakness CWE-327 – Use of a Broken or Risky Cryptographic Algorithm

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Vendor StatusVendor

SUSE

Severity: Medium
Product Status
openSUSE Tumbleweed Fixed
SUSE Linux Enterprise High Performance Computing 15 SP7 Fixed
SUSE Linux Enterprise Micro 5.2 Fixed
SUSE Linux Enterprise Micro 5.3 Fixed
SUSE Linux Enterprise Micro 5.4 Fixed

References

Advisories & patches
PATCH https://github.com/stefanberger/libtpms/commit/33c9ff074cb16c1841ce7d7f33643c17c426743a PATCH https://github.com/stefanberger/libtpms/security/advisories/GHSA-7jxr-4j3g-p34f

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