CVE-2026-52933

CVE-2026-52933 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-835.

Key facts

Description

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.

Frequently asked questions

What is CVE-2026-52933?
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.
How severe is CVE-2026-52933?
CVE-2026-52933 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-52933 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-52933?
CVE-2026-52933 primarily affects Linux Linux Kernel. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-52933?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-52933 have an EU (EUVD) identifier?
Yes. CVE-2026-52933 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38703.
When was CVE-2026-52933 published?
CVE-2026-52933 was published on 2026-06-24 and last updated on 2026-07-08.

References

Affected products (4)

More vulnerabilities in Linux Linux Kernel

All CVEs affecting Linux Linux Kernel →

Other CWE-835 (Loop with Unreachable Exit Condition (Infinite Loop)) vulnerabilities

Browse all CWE-835 (Loop with Unreachable Exit Condition (Infinite Loop)) vulnerabilities →