CVE-2026-52933: io_uring/poll: fix signed comparison in io_poll_get_ownership()
In the Linux kernel, the following vulnerability has been resolved:
iouring/poll: fix signed comparison in iopollgetownership()
iopollgetownership() uses a signed comparison to check whether pollrefs has reached the threshold for the slowpath:
if (unlikely(atomicread(&req->pollrefs) >= IOPOLLREFBIAS))
atomicread() returns int (signed). When IOPOLLCANCELFLAG (BIT(31)) is set in pollrefs, 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 atomicread() result to unsigned int before the comparison, so that the cancel flag is treated as a large positive value and correctly triggers the slowpath.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.6.143.1-1 - Configuration
Fix the signed comparison by casting the atomic_read() result to unsigned int before evaluating `unlikely(atomic_read(&req->poll_refs) >= IO_POLL_REF_BIAS)` so the cancel flag is treated as false and the slowpath is not taken incorrectly.
Linux kernel (io_uring/poll: io_poll_get_ownership) signed comparison/cast of atomic_read(&req->poll_refs) = cast atomic_read() result to unsigned int before comparison
Event History
Frequently Asked Questions
What is the severity of CVE-2026-52933?
The severity of CVE-2026-52933 is rated at risk level 37.
What systems are affected by CVE-2026-52933?
CVE-2026-52933 affects the Linux kernel, specifically in the io_uring/poll functionality.
How do I fix CVE-2026-52933?
To resolve CVE-2026-52933, update your Linux kernel to the latest patched version that addresses this vulnerability.
What are the potential impacts of CVE-2026-52933?
The signed comparison error in CVE-2026-52933 could lead to incorrect handling of poll references, potentially causing instability.
When was CVE-2026-52933 published?
CVE-2026-52933 was published on June 24, 2026.