CVE-2023-52633: um: time-travel: fix time corruption

Severity: medium (CVSS 5.0 v3.1)
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: 2024-04-02 · updated 2026-06-17
Weakness: CWE-787

Description

In the Linux kernel, the following vulnerability has been resolved: um: time-travel: fix time corruption In 'basic' time-travel mode (without =inf-cpu or =ext), we still get timer interrupts. These can happen at arbitrary points in time, i.e. while in timer_read(), which pushes time forward just a little bit. Then, if we happen to get the interrupt after calculating the new time to push to, but before actually finishing that, the interrupt will set the time to a value that's incompatible with the forward, and we'll crash because time goes backwards when we do the forwarding. Fix this by reading the time_travel_time, calculating the adjustment, and doing the adjustment all with interrupts disabled.

Affected products

Linux kernel: before 5.15.149; from 5.16 before 6.1.77; from 6.2 before 6.6.16; from 6.7 before 6.7.4 — fixed in 5.15.149, 6.1.77, 6.6.16, 6.7.4

How to fix

Upgrade to a fixed version: Linux kernel 5.15.149, 6.1.77, 6.6.16, 6.7.4. Check the vendor advisory for mitigations.

References

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