CVE-2026-71226
Description
Memory Corruption via Uncanceled AIO Requests on Error: libkcapi's one-shot AIO path can return an error before all submitted IOCBs are drained, allowing later kernel writes into caller-owned output buffers.
Statement
This Moderate impact flaw in libkcapi affects applications utilizing the one-shot Asynchronous I/O (AIO) interfaces with the KCAPI_INIT_AIO flag. Exploitation requires an error to occur after submitting I/O Control Blocks (IOCBs), followed by the application freeing or reusing output buffers before all kernel completions are processed. This vulnerability does not affect default configurations as it relies on an opt-in AIO setup.
Mitigation
To mitigate this issue, applications should avoid initializing libkcapi handles with the `KCAPI_INIT_AIO` flag, preferring synchronous interfaces instead. If the real AIO path must be enabled, applications must ensure that `outiov` buffers are not immediately freed or reused after an error return, allowing all kernel completions to finish. This operational control prevents delayed kernel writes into potentially reallocated or freed memory.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.3 | N/A | 7.3 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory
The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Confidentiality
Technical Impact: Read Memory
Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.
Acknowledgements
This issue was discovered by Found by AISLE in partnership with Red Hat.
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