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CVE-2026-98935: rtc: dev: zero-initialize struct rtc_wkalrm to prevent information leak

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-23 · updated 2026-10-30

Description

In the Linux kernel, the following vulnerability has been resolved: rtc: dev: zero-initialize struct rtc_wkalrm to prevent information leak The struct rtc_wkalrm has padding holes after the 'pending' member. When returned to userspace via the RTC_WKALRM_RD ioctl, uninitialized kernel stack data residing in these holes may be leaked. Zero-initialize the struct at declaration to eliminate this information leak risk. Fixes smatch warnings: - drivers/rtc/dev.c:392 rtc_dev_ioctl() warn: check that 'alarm' doesn't leak information (struct has a hole after 'pending')

Affected products

• Linux: 5.0 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/00dc50cede96738dadc64b20e671186cddb8a58d
• https://git.kernel.org/stable/c/0ee5c5d804d592a8328a425b9274487d393d3a05
• https://git.kernel.org/stable/c/2838d7bbb551861c25187dfb581ed6e7a56762e9
• https://git.kernel.org/stable/c/a2215eb3cbbd3d9d73cc18c08e3ef53f903443cb
• https://git.kernel.org/stable/c/beda3c9730ad3087d01aa1d0415c40942042ec87
• https://git.kernel.org/stable/c/f84eb9b7b0feeb267a174237d70a857042ce0158

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