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CVE-2026-71225

Libkcapi: iv reuse in libkcapi one-shot symmetric cipher chunking causes cipher state reset across chunk boundaries

Products / packages Stephan Muelle libkcapi · Red Hat Enterprise Linux 10 · Red Hat Enterprise Linux 10.0 Extended Update Support · 6 more

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Severity and exploitation

Not in CISA KEV

KEV coverage does not rule out exploitation.

KEV checked 05/11/2026, 10:05:32 UTC
redhat · CVSS:3.1 · 6.5
Assessment vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

Severity

medium6.5

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Source guidance available

Review the recorded instructions. Guidance may be a workaround rather than a fixed version.

What this means

Libkcapi versions before 1.5.1 are affected by a flaw that reuses the Initialization Vector (IV) for each internal data chunk in one-shot symmetric cipher operations, potentially weakening data confidentiality and integrity. A remote attacker could exploit this by making an application process specially crafted large inputs. This affects libkcapi when used in stateful modes like Counter or Cipher Block Chaining.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

Stephan Muelle · redhat

libkcapi

1 range
redhat version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

0.10.1 → before 1.5.1

semver versions

unaffected

unknown

Other versions: unaffected

Red Hat · redhat

Red Hat Enterprise Linux 10

1 range
redhat version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

unaffected

0:1.5.1-1.el10_2 → before *

rpm versions

unknown

Other versions: affected

Product identifiers (CPE)cpe:/o:redhat:enterprise_linux:10.2

Red Hat · redhat

Red Hat Enterprise Linux 10.0 Extended Update Support

1 range
redhat version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

unaffected

0:1.5.0-6.el10_0 → before *

rpm versions

unknown

Other versions: affected

Product identifiers (CPE)cpe:/o:redhat:enterprise_linux_eus:10.0

Red Hat · redhat

Red Hat Enterprise Linux 8

1 range
redhat version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

unaffected

0:1.4.0-3.el8_10 → before *

rpm versions

unknown

Other versions: affected

Product identifiers (CPE)cpe:/o:redhat:enterprise_linux:8::baseos

Red Hat · redhat

Red Hat Enterprise Linux 9

1 range
redhat version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

unaffected

0:1.4.0-3.el9_8 → before *

rpm versions

unknown

Other versions: affected

Product identifiers (CPE)cpe:/o:redhat:enterprise_linux:9::baseos

Red Hat · redhat

Red Hat Enterprise Linux 9.6 Extended Update Support

1 range
redhat version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

unaffected

0:1.4.0-2.el9_6.1 → before *

rpm versions

unknown

Other versions: affected

Product identifiers (CPE)cpe:/o:redhat:rhel_eus:9.6::baseos

Red Hat · redhat

Red Hat Hardened Images

1 range
redhat version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

unaffected

1.5.1-0.1.hum1 → before *

rpm versions

unknown

Other versions: affected

Product identifiers (CPE)cpe:/a:redhat:hummingbird:1

Red Hat · redhat

Red Hat OpenShift Container Platform 4

0 ranges
redhat version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

unaffected

unknown

Other versions: affected

Product identifiers (CPE)cpe:/a:redhat:openshift:4

Red Hat · redhat

Red Hat OpenShift Container Platform 4

0 ranges
redhat version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

unaffected

unknown

Other versions: affected

Product identifiers (CPE)cpe:/a:redhat:openshift:4

Red Hat · redhat

Red Hat OpenShift Container Platform 5

0 ranges
redhat version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

unaffected

unknown

Other versions: affected

Product identifiers (CPE)cpe:/a:redhat:openshift:5
Automatic dependency matching is unavailable for this record. Use the product evidence and publisher’s instructions to check your installation.

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

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.

redhat guidance ↗

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher 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.

References

8 sources
access.redhat.com/errata/RHSA-2026:56985
Vendor advisoryredhat
access.redhat.com/errata/RHSA-2026:67265
Vendor advisoryredhat
access.redhat.com/errata/RHSA-2026:67266
Vendor advisoryredhat
access.redhat.com/errata/RHSA-2026:67267
Vendor advisoryredhat
access.redhat.com/errata/RHSA-2026:69285
Vendor advisoryredhat
access.redhat.com/errata/RHSA-2026:87712
Vendor advisoryredhat
View 2 more references
access.redhat.com/security/cve/CVE-2026-71225
Security advisoryredhat
bugzilla.redhat.com/show_bug.cgi
Source referenceredhat

Inside the record

Evidence available

Package identity · not supplied
Version evidence
Remediation guidance
Weakness classification
Additional publishers

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-71225

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-330 ↗

Use of Insufficiently Random Values

redhat

Related →
Contributing organizations · 2
redhat

Assigning organization

2026-11-02
CISA-ADP

Additional data publisher

2026-08-05

Timeline

All times UTC

  1. Advisory published

    Publication date supplied by the source.

  2. Source updated

    Latest modification date supplied by the source.

  3. Last imported by cve.new

    Latest catalog import, not the date we first saw this advisory.

What changed

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Large field values are marked as truncated previews. Original source snapshots remain retained.