VulnerabilityPublished 26 Jun 2026Updated 21 Oct 2026

CVE-2026-53321: Linux kernel · io_uring/napi: cap busy_poll_to 10 msec

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in df8599ee18c0e5fe343ffe0b4c379636b8bb839a : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in df8599ee18c0e5fe343ffe0b4c379636b8bb839a, cb3af525f8dfb8930f0c123e5755fa967a12d5c1, 42785efe813e5a7d815f3b6be126e1bc0d12d2b6 +1

Exploitation evidence

Disclosed: evidence found.
CVE published 26 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to df8599ee18c0e5fe343ffe0b4c379636b8bb839a, cb3af525f8dfb8930f0c123e5755fa967a12d5c1, 42785efe813e5a7d815f3b6be126e1bc0d12d2b6 or 39767f944a8c9e696566c37ad5b20131406c4b8d.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 8d0c12a80cdeb80d5e0510e96d38fe551ed8e9b5, < df8599ee18c0e5fe343ffe0b4c379636b8bb839a	Fixed in df8599ee18c0e5fe343ffe0b4c379636b8bb839a
LinuxLinux	Affected ≥ 8d0c12a80cdeb80d5e0510e96d38fe551ed8e9b5, < cb3af525f8dfb8930f0c123e5755fa967a12d5c1	Fixed in cb3af525f8dfb8930f0c123e5755fa967a12d5c1
LinuxLinux	Affected ≥ 8d0c12a80cdeb80d5e0510e96d38fe551ed8e9b5, < 42785efe813e5a7d815f3b6be126e1bc0d12d2b6	Fixed in 42785efe813e5a7d815f3b6be126e1bc0d12d2b6
LinuxLinux	Affected ≥ 8d0c12a80cdeb80d5e0510e96d38fe551ed8e9b5, < 39767f944a8c9e696566c37ad5b20131406c4b8d	Fixed in 39767f944a8c9e696566c37ad5b20131406c4b8d
LinuxLinux	Affected =6.9	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring/napi: cap busy_poll_to 10 msec Currently there's no cap on the maximum amount of time that napi is allowed to poll if no events are found, which can lead to kernel complaints on a task being stuck as there's no conditional rescheduling done within that loop. Just cap it to 10 msec in total, that's already way above any kind of sane value that will reap any benefits, yet low enough that it's nowhere near being able to trigger preemption complaints.

References

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