VulnerabilityPublished 17 Sep 2026Updated 21 Oct 2026

CVE-2026-90187: Linux kernel · null_blk: free zones array on device power-off

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in b2437d37fcc31fce8a5da1cc1739e284814d2491 : 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 b2437d37fcc31fce8a5da1cc1739e284814d2491, 056be41932c95aabdb3c2967d1ef4978f17a0225, 08a31a2cc3d1cea67ccd292d01511cd0a72d4656 +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 ≥ ca4b2a011948fae4e4d31490107db4926385a983, < b2437d37fcc31fce8a5da1cc1739e284814d2491	Fixed in b2437d37fcc31fce8a5da1cc1739e284814d2491
LinuxLinux	Affected ≥ ca4b2a011948fae4e4d31490107db4926385a983, < 056be41932c95aabdb3c2967d1ef4978f17a0225	Fixed in 056be41932c95aabdb3c2967d1ef4978f17a0225
LinuxLinux	Affected ≥ ca4b2a011948fae4e4d31490107db4926385a983, < 08a31a2cc3d1cea67ccd292d01511cd0a72d4656	Fixed in 08a31a2cc3d1cea67ccd292d01511cd0a72d4656
LinuxLinux	Affected ≥ ca4b2a011948fae4e4d31490107db4926385a983, < 2a6357a9b935a34f5508618fee8a7fffbf7722a8	Fixed in 2a6357a9b935a34f5508618fee8a7fffbf7722a8
LinuxLinux	Affected ≥ ca4b2a011948fae4e4d31490107db4926385a983, < 0a3afab87124171022fb3579502fa38ef5b311c9	Fixed in 0a3afab87124171022fb3579502fa38ef5b311c9
LinuxLinux	Affected =4.19	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: null_blk: free zones array on device power-off null_init_zoned_dev() allocates dev->zones when a zoned device is powered on, but null_del_dev() never frees it on power-off; dev->zones is only freed later in null_free_dev(), when the configfs directory is removed. If the device is powered off and then on again, null_init_zoned_dev() allocates a new array and overwrites the dev->zones pointer, leaking the previous allocation each power cycle. Free dev->zones in null_del_dev() via null_free_zoned_dev() to solve it. And calling null_free_zoned_dev() in null_free_dev() is no longer necessary because every caller already invokes null_del_dev() first: via nullb_group_drop_item() before nullb_device_release(), in the null_add_dev() error path of null_create_dev(), and in null_destroy_dev(). Remove the redundant call. And take &lock around zone_cond_store() in the two store wrappers to serialize dev->zones check-and-deref against its alloc/free, which already run under &lock. The reason there was no problem before is that only nullb_device_release() or null_exit() frees the dev->zones, which guarantees that subsequent users won't access the configfs interface.

References

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