CVE-2025-21655
4.7
MEDIUM
CVSS 3.1
EPSS 0.02%
Description
In the Linux kernel, the following vulnerability has been resolved: io_uring/eventfd: ensure io_eventfd_signal() defers another RCU period io_eventfd_do_signal() is invoked from an RCU callback, but when dropping the reference to the io_ev_fd, it calls io_eventfd_free() directly if the refcount drops to zero. This isn't correct, as any potential freeing of the io_ev_fd should be deferred another RCU grace period. Just call io_eventfd_put() rather than open-code the dec-and-test and free, which will correctly defer it another RCU grace period.
How to fix CVE-2025-21655
To remediate CVE-2025-21655, upgrade the affected package to a fixed version below.
- —upgrade to 6.1.128-1 or later
- —upgrade to 6.1.128-1~deb11u1 or later
Is CVE-2025-21655 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 6.1.128-1
- from 0, < 6.1.128-1~deb11u1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM4.7 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H |