CVE-2026-89905
LoongArch: BPF: Move arena register slot below TCC context
Description
In the Linux kernel, the following vulnerability has been resolved: LoongArch: BPF: Move arena register slot below TCC context Currently, the stack layout places the optional arena register slot above the tail call counter context. When arena_vm_start is dynamically enabled, it shifts the relative offset of the tcc_ptr slot within the stack frame, causing hardcoded tracking macros to mismatch and leading to memory misalignment or corruption potentially. To fix this, move the arena register save and restore sequences below the tail call counter context slots in both build_prologue() and the epilogue. Update __build_epilogue() to insert a proper offset decrement to safely skip the unneeded tcc_ptr reading block while accurately aligning with the relocated arena slot at the very bottom. With this patch, the tcc_ptr slot is always positioned at a fixed distance directly underneath the base callee-saved registers that is independent of whether the arena features are on.
INFO
Published Date :
Sept. 16, 2026, 11:16 a.m.
Last Modified :
Sept. 16, 2026, 11:16 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Apply the Linux kernel patch to relocate the arena register slot.
- Update prologue and epilogue sequences in build_prologue().
- Modify __build_epilogue() for correct offset handling.
- Ensure fixed tcc_ptr slot positioning.
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-2026-89905.
| URL | Resource |
|---|---|
| https://git.kernel.org/stable/c/cd7e356b07a27e91394838cf3fb655862b519294 | |
| https://git.kernel.org/stable/c/f0e4d069cb47cf4f8dc4f6bc104e0671155aa3b9 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-89905 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-2026-89905
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-2026-89905 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-89905 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.
-
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: LoongArch: BPF: Move arena register slot below TCC context Currently, the stack layout places the optional arena register slot above the tail call counter context. When arena_vm_start is dynamically enabled, it shifts the relative offset of the tcc_ptr slot within the stack frame, causing hardcoded tracking macros to mismatch and leading to memory misalignment or corruption potentially. To fix this, move the arena register save and restore sequences below the tail call counter context slots in both build_prologue() and the epilogue. Update __build_epilogue() to insert a proper offset decrement to safely skip the unneeded tcc_ptr reading block while accurately aligning with the relocated arena slot at the very bottom. With this patch, the tcc_ptr slot is always positioned at a fixed distance directly underneath the base callee-saved registers that is independent of whether the arena features are on. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/89xxx/CVE-2026-89905.json">CVE-2026-89905</a> Added Reference https://git.kernel.org/stable/c/cd7e356b07a27e91394838cf3fb655862b519294 Added Reference https://git.kernel.org/stable/c/f0e4d069cb47cf4f8dc4f6bc104e0671155aa3b9