# CVE-2026-89905: linux: In the Linux kernel, the following vulnerability has been resolved:  LoongArch: BPF: Move arena register slot below T...

CVE-2026-89905 is fixed in linux on 1 platform by DEBIAN-CVE-2026-89905 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-89905
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0020
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 16, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-89905](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89905.md) | Sep 23, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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