CVE-2026-89847
Description
A flaw was found in the Linux kernel's qla2xxx SCSI driver. A double completion scenario can occur during the asynchronous I/O control block (IOCB) timeout handling. This can lead to a use-after-free vulnerability, where the system attempts to write to memory that has already been released. A local attacker could potentially exploit this to cause a denial of service or escalate privileges.
Statement
A race in qla2xxx async IOCB timeout handling can lead to double completion of the same SRB. If the response ISR completes the handle first, the submitter can return and reclaim the on-stack completion while the timeout path still later calls sp done and complete on the stale pointer. This is a use-after-free in a storage driver completion path and can cause a kernel crash. For the CVSS the PR:N is used because a malicious or compromised Fibre Channel endpoint or fabric element may influence completion timing without a local account on the host. The issue is adjacent-network reachable in Fibre Channel or storage fabric terms, not generally Internet reachable over TCP/IP. Impact is at least denial of service and in the paranoid case may include confidentiality or integrity impact because the bug writes through a stale completion pointer into reclaimed stack memory.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
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 | 5.3 | N/A | 9.8 |
| Attack Vector | Adjacent Network | N/A | Network |
| Attack Complexity | High | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | High |
| Integrity Impact | None | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.
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