CVE-2026-52933
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk2th percentile — higher than 2% of all known CVEs
Summary
In the Linux kernel, a vulnerability was found in the io_uring/poll mechanism where a signed comparison in io_poll_get_ownership() prevented the slowpath from being taken when the cancel flag (IO_POLL_CANCEL_FLAG) was set. This could lead to improper handling of cancellation operations.
Risk Assessment
The risk is that an attacker could exploit this flaw to trigger use-after-free or other memory corruption issues, potentially leading to privilege escalation or system crash.
Recommendation
Immediately update the Linux kernel to a version containing the fix (commit casting to unsigned int). Monitor official security advisories from your Linux distribution.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: io_uring/poll: fix signed comparison in io_poll_get_ownership() io_poll_get_ownership() uses a signed comparison to check whether poll_refs has reached the threshold for the slowpath: if (unlikely(atomic_read(&req->poll_refs) >= IO_POLL_REF_BIAS)) atomic_read() returns int (signed). When IO_POLL_CANCEL_FLAG (BIT(31)) is set in poll_refs, the value becomes negative in signed arithmetic, so the >= 128 comparison always evaluates to false and the slowpath is never taken. Fix this by casting the atomic_read() result to unsigned int before the comparison, so that the cancel flag is treated as a large positive value and correctly triggers the slowpath.