VulnerabilityPublished 17 Sep 2026Updated 30 Oct 2026

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

Source GCVE Database

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Authoritative record:CVE-2026-90183· Medium

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

Data as of 30 Oct 2026, 19:03 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in b6449a915d1826e1450f6368fc379fe44caa06ca, 27573278b1cbc2313ebd31309ac18ac6179b828a, 8935bf22c0a0db517a7f72f7097300e05dd852f5 +3

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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.

ghsa-62h3-pvxj-c2v2

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, < 27573278b1cbc2313ebd31309ac18ac6179b828a	Fixed in 27573278b1cbc2313ebd31309ac18ac6179b828a
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

Description

A vulnerability in the Linux kernel blk-iolatency subsystem causes delay state to persist improperly when freeing policy data. This leads to continuous throttling of I/O operations for affected control groups and their descendants, resulting in degraded performance such as reduced readahead and throttled anonymous memory allocation.

Impact

Affected Linux kernel control groups experience persistent I/O throttling even when no latency target is set, leading to reduced readahead and throttled anonymous memory allocations. This can degrade system performance for tasks within the affected cgroups and their descendants for as long as the cgroup exists.

Summary

The Linux kernel blk-iolatency subsystem had a flaw where delay state was not cleared when freeing policy data, causing blkcg->congestion_count to remain elevated indefinitely. This results in blk_cgroup_congested() returning true for all tasks in the affected cgroup and descendants, causing persistent I/O throttling. The issue arises because iolatency_pd_offline() only clears delay on a nonzero to zero transition, missing peers with min_lat_nsec == 0. The fix clears the delay in iolatency_pd_free(), ensuring no stale delay state remains after policy data is freed.

References

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