VulnerabilityPublished 17 Sep 2026Updated 21 Oct 2026

CVE-2026-90182: Linux kernel · blk-iocost: clear delay state when freeing policy data

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in b399a88eb8b16c5a1a3645fd49ff507fb82b363c : 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 b399a88eb8b16c5a1a3645fd49ff507fb82b363c, b9c16db833e3ff15d923282f94dddf0e10fab8c0, 97cb95d2148835ae86ff916b145aef332d40439d +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 ≥ 7caa47151ab2e644dd221f741ec7578d9532c9a3, < b399a88eb8b16c5a1a3645fd49ff507fb82b363c	Fixed in b399a88eb8b16c5a1a3645fd49ff507fb82b363c
LinuxLinux	Affected ≥ 7caa47151ab2e644dd221f741ec7578d9532c9a3, < b9c16db833e3ff15d923282f94dddf0e10fab8c0	Fixed in b9c16db833e3ff15d923282f94dddf0e10fab8c0
LinuxLinux	Affected ≥ 7caa47151ab2e644dd221f741ec7578d9532c9a3, < 97cb95d2148835ae86ff916b145aef332d40439d	Fixed in 97cb95d2148835ae86ff916b145aef332d40439d
LinuxLinux	Affected ≥ 7caa47151ab2e644dd221f741ec7578d9532c9a3, < 8b4d0b1b3079bbe9a5366e2c8020eb22926733b6	Fixed in 8b4d0b1b3079bbe9a5366e2c8020eb22926733b6
LinuxLinux	Affected ≥ 7caa47151ab2e644dd221f741ec7578d9532c9a3, < 6b59f976db5def818829fc1eb4efc0a5c8c2f0cf	Fixed in 6b59f976db5def818829fc1eb4efc0a5c8c2f0cf
LinuxLinux	Affected =5.4	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: blk-iocost: clear delay state when freeing policy data iocg_kick_delay() turns sufficiently large debt into an explicit block-cgroup delay with blkcg_set_delay(), setting blkg->use_delay to -1 and incrementing blkcg->congestion_count. Clearing it again depends on iocg_kick_delay() running from the period timer, the waitq timer or the issue path. ioc_pd_free() removes the iocg from active_iocgs and cancels its waitq timer, and no further bios can arrive, so once it has run nothing is left which can reduce the debt and clear the delay. The blkcg stays marked congested for the rest of its life. blk_cgroup_congested() then returns true for every task in that cgroup and its descendants: 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 it explicitly, after the list removal and the synchronous hrtimer_cancel() so that neither timer processing nor an I/O path can 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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