CVE-2026-89856
scsi: qla2xxx: Clamp MSI-X derived queue counts to avoid truncation
Description
In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Clamp MSI-X derived queue counts to avoid truncation ha->msix_count is u16, but ha->max_req_queues, ha->max_rsp_queues and ha->max_qpairs are u8. Deriving the queue count as "ha->max_req_queues = ha->msix_count - 1" therefore truncates: a board (or a misconfigured/malicious hot-plugged device) advertising 257 MSI-X vectors yields msix_count - 1 == 256, which truncates to 0. An MSI-X count of 1 zeroes it as well, and in target mode the subsequent "ha->max_req_queues--" then underflows 0 to 255. When the count is 0, qla2x00_alloc_queues() calls kzalloc_objs(struct req_que *, 0), which returns ZERO_SIZE_PTR. That is not NULL, so the allocation check passes and the following "ha->req_q_map[0] = req" dereferences ZERO_SIZE_PTR, corrupting memory or crashing the kernel. Add qla_calc_queue_count() to clamp the derived value into [1, QLA_MAX_QUEUES - 1] so it always fits in u8 and is never zero, and use it at all three derivation sites (qla25xx_iospace_config(), qla83xx_iospace_config() and qla24xx_enable_msix()). Also guard the target-mode decrement so it cannot reintroduce a zero (which would in turn underflow max_qpairs).
INFO
Published Date :
Sept. 16, 2026, 11:16 a.m.
Last Modified :
Sept. 16, 2026, 3:18 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Update the Linux kernel to the latest version.
- Apply the specific patch for qla2xxx driver.
- Ensure queue counts are clamped to valid ranges.
- Guard against underflow in target mode.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-89856.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-89856 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-89856
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-89856 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-89856 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 16, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 16, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Clamp MSI-X derived queue counts to avoid truncation ha->msix_count is u16, but ha->max_req_queues, ha->max_rsp_queues and ha->max_qpairs are u8. Deriving the queue count as "ha->max_req_queues = ha->msix_count - 1" therefore truncates: a board (or a misconfigured/malicious hot-plugged device) advertising 257 MSI-X vectors yields msix_count - 1 == 256, which truncates to 0. An MSI-X count of 1 zeroes it as well, and in target mode the subsequent "ha->max_req_queues--" then underflows 0 to 255. When the count is 0, qla2x00_alloc_queues() calls kzalloc_objs(struct req_que *, 0), which returns ZERO_SIZE_PTR. That is not NULL, so the allocation check passes and the following "ha->req_q_map[0] = req" dereferences ZERO_SIZE_PTR, corrupting memory or crashing the kernel. Add qla_calc_queue_count() to clamp the derived value into [1, QLA_MAX_QUEUES - 1] so it always fits in u8 and is never zero, and use it at all three derivation sites (qla25xx_iospace_config(), qla83xx_iospace_config() and qla24xx_enable_msix()). Also guard the target-mode decrement so it cannot reintroduce a zero (which would in turn underflow max_qpairs). Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/89xxx/CVE-2026-89856.json">CVE-2026-89856</a> Added Reference https://git.kernel.org/stable/c/2efe50b2da829909023de4a2eb87badb7cfa53cc Added Reference https://git.kernel.org/stable/c/33c77254e6e91f37c72c7fad4051777452b10de8 Added Reference https://git.kernel.org/stable/c/7a448f5ed0b283dbde4e9183dd1e98c221432dab Added Reference https://git.kernel.org/stable/c/802068b9b683b8008fcccbf6e9ad133e597ec87c Added Reference https://git.kernel.org/stable/c/9eeddbeaa896f39d943644b16d83a6ad0ceab255 Added Reference https://git.kernel.org/stable/c/cf623d32761b00f221a9cfded3303d56e84b429d Added Reference https://git.kernel.org/stable/c/e80adfeac61b4d5db7ffe0f5af43999c33a4145e Added Reference https://git.kernel.org/stable/c/ebfd35c64433821bd5619a6d07ccc2df8b5b1de3