Libkcapi: iv reuse in libkcapi one-shot symmetric cipher chunking causes cipher state reset across chunk boundaries
Priority LOW 29CWE-330Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- High · Low · None
- Fix status
- Partial Red Hat: 6 fixed, 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00345 28th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial libkcapi (Stephan Muelle): 1.5.1Red Hat: 6 advisoriesRed Hat: 6 fixed, 2 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Stephan Muelle | libkcapi | 0.10.1 to before 1.5.1 | 1.5.1 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 10 | — | 1.5.1-1.el10_2 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | — | 1.5.0-6.el10_0 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 8 | — | 1.4.0-3.el8_10 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 9 | — | 1.4.0-3.el9_8 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | — | 1.4.0-2.el9_6.1 | Patch available | CNA |
| Red Hat | Red Hat Hardened Images | — | 1.5.1-0.1.hum1 | Patch available | CNA |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift Container Platform 5 | — | — | No fix listed | CNA |
- libkcapi VendorStephan Muelle Affected 0.10.1 to before 1.5.1 Fixed in 1.5.1 Patch available CNA
- Red Hat Enterprise Linux 10 VendorRed Hat Affected — Fixed in 1.5.1-1.el10_2 Patch available CNA
- Red Hat Enterprise Linux 10.0 Extended Update Support VendorRed Hat Affected — Fixed in 1.5.0-6.el10_0 Patch available CNA
- Red Hat Enterprise Linux 8 VendorRed Hat Affected — Fixed in 1.4.0-3.el8_10 Patch available CNA
- Red Hat Enterprise Linux 9 VendorRed Hat Affected — Fixed in 1.4.0-3.el9_8 Patch available CNA
- Red Hat Enterprise Linux 9.6 Extended Update Support VendorRed Hat Affected — Fixed in 1.4.0-2.el9_6.1 Patch available CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in 1.5.1-0.1.hum1 Patch available CNA
- Red Hat OpenShift Container Platform 4 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift Container Platform 4 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift Container Platform 5 VendorRed Hat Affected — Fixed in — No fix listed CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Red Hat |
| cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:* | 4.0 | Vulnerable | Red Hat |
| cpe:2.3:a:smuellerdd:libkcapi:*:*:*:*:*:*:*:* | 0.10.1 to before 1.5.1 | Vulnerable | smuellerDD |
| cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* | 8.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* | 9.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* | 10.0 | Vulnerable | Red Hat |
- cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Red Hat
- cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:* Versions 4.0 Vulnerable ·Red Hat
- cpe:2.3:a:smuellerdd:libkcapi:*:*:*:*:*:*:*:* Versions 0.10.1 to before 1.5.1 Vulnerable ·smuellerDD
- cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Red Hat
Remediation
- Fix · CNA libkcapi (Stephan Muelle) Fixed in 1.5.1
Red Hat 6 advisories
- RHSA-2026:87712 Released 2026-10-22 · Red Hat rating Moderatelibkcapi security update
- Red Hat Enterprise Linux BaseOS EUS (v.9.6) libkcapi-1.4.0-2.el9_6.1, libkcapi-hmaccalc-1.4.0-2.el9_6.1
- RHSA-2026:69285 Released 2026-09-21 · Red Hat rating Moderatelibkcapi security update
- Red Hat Enterprise Linux BaseOS EUS (v. 10.0) libkcapi-1.5.0-6.el10_0
- RHSA-2026:67265 Released 2026-09-14 · Red Hat rating Moderatelibkcapi security, bug fix, and enhancement update
- Red Hat Enterprise Linux BaseOS (v. 9) libkcapi-1.4.0-3.el9_8, libkcapi-hmaccalc-1.4.0-3.el9_8
Show 3 more Red Hat advisories
- RHSA-2026:67267 Released 2026-09-14 · Red Hat rating Moderatelibkcapi security, bug fix, and enhancement update
- Red Hat Enterprise Linux BaseOS (v. 10) libkcapi-1.5.1-1.el10_2, libkcapi-hasher-1.5.1-1.el10_2, libkcapi-hmaccalc-1.5.1-1.el10_2
- RHSA-2026:67266 Released 2026-09-14 · Red Hat rating Moderatelibkcapi security update
- Red Hat Enterprise Linux BaseOS (v. 8) libkcapi-1.4.0-3.el8_10, libkcapi-hmaccalc-1.4.0-3.el8_10
- RHSA-2026:56985 Released 2026-08-19 · Red Hat rating ModerateRed Hat Hardened Images RPMs Security Update
- Red Hat Hardened Images libkcapi-1.5.1-0.1.hum1@aarch64, libkcapi-1.5.1-0.1.hum1@src, libkcapi-1.5.1-0.1.hum1@x86_64 +14
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Advisory ·
Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support and 7 more products — RHSA-2026:56985
3 records Highest priority Priority LOW 3 LOW
Other records, highest priority first
- TI-2026-49900 Libkcapi: memory corruption via uncanceled aio requests on error in libkcapi's one-shot aio pathPriority LOW 31
- TI-2026-49901 Infinite loop in Stephan Muelle libkcapiPriority LOW 23
- Advisory ·
Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support and 7 more products — RHSA-2026:67265
3 records Highest priority Priority LOW 3 LOW
Other records, highest priority first
- TI-2026-49900 Libkcapi: memory corruption via uncanceled aio requests on error in libkcapi's one-shot aio pathPriority LOW 31
- TI-2026-49901 Infinite loop in Stephan Muelle libkcapiPriority LOW 23
Show 4 more groups
- Advisory ·
Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support and 7 more products — RHSA-2026:67266
3 records Highest priority Priority LOW 3 LOW
Other records, highest priority first
- TI-2026-49900 Libkcapi: memory corruption via uncanceled aio requests on error in libkcapi's one-shot aio pathPriority LOW 31
- TI-2026-49901 Infinite loop in Stephan Muelle libkcapiPriority LOW 23
- Advisory ·
Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support and 7 more products — RHSA-2026:67267
3 records Highest priority Priority LOW 3 LOW
Other records, highest priority first
- TI-2026-49900 Libkcapi: memory corruption via uncanceled aio requests on error in libkcapi's one-shot aio pathPriority LOW 31
- TI-2026-49901 Infinite loop in Stephan Muelle libkcapiPriority LOW 23
- Advisory ·
Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support and 7 more products — RHSA-2026:69285
3 records Highest priority Priority LOW 3 LOW
Other records, highest priority first
- TI-2026-49900 Libkcapi: memory corruption via uncanceled aio requests on error in libkcapi's one-shot aio pathPriority LOW 31
- TI-2026-49901 Infinite loop in Stephan Muelle libkcapiPriority LOW 23
- Advisory ·
Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support and 7 more products — RHSA-2026:87712
3 records Highest priority Priority LOW 3 LOW
Other records, highest priority first
- TI-2026-49900 Libkcapi: memory corruption via uncanceled aio requests on error in libkcapi's one-shot aio pathPriority LOW 31
- TI-2026-49901 Infinite loop in Stephan Muelle libkcapiPriority LOW 23
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:67267 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2026:67266 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:67265 |
| Red Hat Enterprise Linux BaseOS EUS (v. 10.0) | Fixed | RHSA-2026:69285 |
| Red Hat Enterprise Linux BaseOS EUS (v.9.6) | Fixed | RHSA-2026:87712 |
| Red Hat Hardened Images | Fixed | RHSA-2026:56985 |
Not affected: 2 products
- Red Hat Enterprise Linux BaseOS EUS (v. 10.0)
- Red Hat Enterprise Linux BaseOS EUS (v.9.6)
Timeline
- 2026-10-02 Threatist record created from CVE-2026-71225
- 2026-10-03 Alias added: GHSA-qv62-qmw8-96h9
- 2026-10-23 Fix available: libkcapi@0:1.4.0-2.el9_6.1 · CNA
- 2026-10-23 1 new reference · CNA
- 2026-10-23 Fix available: RHSA-2026:87712 · Red Hat
- 2026-10-23 Fix available: Red Hat Enterprise Linux BaseOS EUS (v.9.6) · Red Hat
- 2026-11-02 Affected versions changed · CNA
- 2026-11-02 Affected versions changed · Red Hat
References
More Red Hat Enterprise Linux vulnerabilities
- TI-2019-08259 Underflow in PHP-FPM can lead to RCE KEVCVSS 3.1CRITICAL 9.8
- TI-2018-10530 Code injection in [UNKNOWN] RichFaces KEVCVSS 3.1CRITICAL 9.8
- TI-2014-05975 GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed… KEVCVSS 3.1CRITICAL 9.8
- TI-2014-05157 GNU Bash through 4.3 processes trailing strings after function definitions in the values… KEVCVSS 3.1CRITICAL 9.8
- TI-2025-23530 Sudo before 1.9.17p1 allows local users to obtain root access because /etc/nsswitch.conf… KEVCVSS 3.1CRITICAL 9.3
- TI-2021-17490 mod_proxy SSRF KEVCVSS 3.1CRITICAL 9.0
Sources
- CVE-2026-71225 · CVE Program
- CVE-2026-71225 · NVD
- FIRST EPSS
- GHSA-qv62-qmw8-96h9 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-71225 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences