A flaw was found in libkcapi. When performing one-shot symmetric cipher operations on large inputs (over 64 KiB) in stateful modes such as Counter (CTR) or Cipher Block Chaining (CBC), the library improperly reuses the Initialization Vector (IV) for each internal data chunk. A remote attacker could potentially exploit this by making an application that uses libkcapi process specially crafted large inputs. This can lead to a significant weakening of data confidentiality, as the repeated IV use can expose relationships in encrypted plaintext, and may also affect data integrity by causing incorrect cryptographic processing.

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Red Hat Red Hat Enterprise Linux 10 affected —
Red Hat Red Hat Enterprise Linux 8 affected —
Red Hat Red Hat Enterprise Linux 9 affected —
Red Hat Red Hat Hardened Images affected —
Red Hat Red Hat OpenShift Container Platform 4 affected —

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Advisories

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Fixes

Solution

No solution given by the vendor.

Workaround

To mitigate this issue, applications using `libkcapi` should avoid the one-shot symmetric cipher APIs for inputs exceeding 64 KiB when continuous-message semantics are critical. Instead, prefer the streaming interface for processing large messages, or ensure one-shot inputs remain below the internal chunking threshold to guarantee the IV is applied consistently throughout the operation.

References
Link Providers
https://access.redhat.com/security/cve/CVE-2026-71225 cve-icon
https://bugzilla.redhat.com/show_bug.cgi?id=2462011 cve-icon
History

Wed, 05 Aug 2026 12:30:00 +0000

Type Values Removed Values Added
Description A flaw was found in libkcapi. When performing one-shot symmetric cipher operations on large inputs (over 64 KiB) in stateful modes such as Counter (CTR) or Cipher Block Chaining (CBC), the library improperly reuses the Initialization Vector (IV) for each internal data chunk. A remote attacker could potentially exploit this by making an application that uses libkcapi process specially crafted large inputs. This can lead to a significant weakening of data confidentiality, as the repeated IV use can expose relationships in encrypted plaintext, and may also affect data integrity by causing incorrect cryptographic processing.
Title Libkcapi: iv reuse in libkcapi one-shot symmetric cipher chunking causes cipher state reset across chunk boundaries
First Time appeared Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
Weaknesses CWE-330
CPEs cpe:/a:redhat:hummingbird:1
cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-08-05T14:21:01.348Z

Reserved: 2026-08-05T09:15:14.859Z

Link: CVE-2026-71225

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-05T13:30:05Z

Weaknesses