VulnerabilityPublished 17 Sep 2026Updated 21 Oct 2026

CVE-2026-90183: Linux kernel · blk-iolatency: clear delay state when freeing policy data

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in b6449a915d1826e1450f6368fc379fe44caa06ca : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in b6449a915d1826e1450f6368fc379fe44caa06ca, 8935bf22c0a0db517a7f72f7097300e05dd852f5, 53ccb4b967edc5f82ff6f9c066fb96c31aa7561a +2

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Sep 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 to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ d70675121546c35feaceebf7ed9caed8716640f3, < b6449a915d1826e1450f6368fc379fe44caa06ca	Fixed in b6449a915d1826e1450f6368fc379fe44caa06ca
LinuxLinux	Affected ≥ d70675121546c35feaceebf7ed9caed8716640f3, < 8935bf22c0a0db517a7f72f7097300e05dd852f5	Fixed in 8935bf22c0a0db517a7f72f7097300e05dd852f5
LinuxLinux	Affected ≥ d70675121546c35feaceebf7ed9caed8716640f3, < 53ccb4b967edc5f82ff6f9c066fb96c31aa7561a	Fixed in 53ccb4b967edc5f82ff6f9c066fb96c31aa7561a
LinuxLinux	Affected ≥ d70675121546c35feaceebf7ed9caed8716640f3, < 5c6593422eb3c3a21505436ccf74599a433584c8	Fixed in 5c6593422eb3c3a21505436ccf74599a433584c8
LinuxLinux	Affected ≥ d70675121546c35feaceebf7ed9caed8716640f3, < 02f1b90ab33ef99c89dd96a385b432ff57abc64d	Fixed in 02f1b90ab33ef99c89dd96a385b432ff57abc64d
LinuxLinux	Affected =4.19	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: blk-iolatency: clear delay state when freeing policy data io.latency can throttle a group which has no latency target of its own. When a sibling misses its target, check_scale_change() scales down its peers, and a peer that reaches queue depth one gets blkcg_use_delay() called on it on every further scale-down, even with min_lat_nsec == 0. iolatency_pd_offline() resets the target through iolatency_set_min_lat_nsec(), which clears the delay only on a nonzero to zero transition, so it never clears such a peer. Freeing the policy data then leaves blkg->use_delay set and blkcg->congestion_count elevated with nothing left that can drop it. blk_cgroup_congested() then returns true for every task in that cgroup and its descendants for as long as the cgroup lives: page_cache_sync_ra() cuts readahead to a single page, page_cache_async_ra() skips it altogether, and __folio_throttle_swaprate() takes swap_avail_lock and schedules a throttle on anonymous folio allocation. Clear the delay in iolatency_pd_free(). By then bio-held blkg references have drained, or the queue is frozen for policy deactivation, so check_scale_change() cannot re-arm it. The free callback can also see policy data which was never attached to a blkg, hence the pd->blkg check.

References

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