VulnerabilityPublished 22 Aug 2025Updated 5 Nov 2026

CVE-2025-38621: Linux kernel · md: make rdev_addable usable for rcu mode

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in d713e105a6137d3f54f09d4d9e2273482057ca17 : update Linux kernel when convenient.

Data as of 5 Nov 2026, 23:23 UTC

Severity

Unrated

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

Thin evidence

One scorer or none

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.

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-05.

Patch

Available – fixed in d713e105a6137d3f54f09d4d9e2273482057ca17, b5fbe940862339cdcc34dea7a057ad18d18fa137, 13017b427118f4311471ee47df74872372ca8482

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Aug 2025
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 5 Nov 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.

What to do

Upgrade Linux kernel to d713e105a6137d3f54f09d4d9e2273482057ca17, b5fbe940862339cdcc34dea7a057ad18d18fa137 or 13017b427118f4311471ee47df74872372ca8482.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ bc08041b32abe6c9824f78735bac22018eabfc06, < d713e105a6137d3f54f09d4d9e2273482057ca17	Fixed in d713e105a6137d3f54f09d4d9e2273482057ca17
LinuxLinux	Affected ≥ bc08041b32abe6c9824f78735bac22018eabfc06, < b5fbe940862339cdcc34dea7a057ad18d18fa137	Fixed in b5fbe940862339cdcc34dea7a057ad18d18fa137
LinuxLinux	Affected ≥ bc08041b32abe6c9824f78735bac22018eabfc06, < 13017b427118f4311471ee47df74872372ca8482	Fixed in 13017b427118f4311471ee47df74872372ca8482
LinuxLinux	Affected =6.7	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: md: make rdev_addable usable for rcu mode Our testcase trigger panic: BUG: kernel NULL pointer dereference, address: 00000000000000e0 ... Oops: Oops: 0000 [#1] SMP NOPTI CPU: 2 UID: 0 PID: 85 Comm: kworker/2:1 Not tainted 6.16.0+ #94 PREEMPT(none) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 Workqueue: md_misc md_start_sync RIP: 0010:rdev_addable+0x4d/0xf0 ... Call Trace: <TASK> md_start_sync+0x329/0x480 process_one_work+0x226/0x6d0 worker_thread+0x19e/0x340 kthread+0x10f/0x250 ret_from_fork+0x14d/0x180 ret_from_fork_asm+0x1a/0x30 </TASK> Modules linked in: raid10 CR2: 00000000000000e0 ---[ end trace 0000000000000000 ]--- RIP: 0010:rdev_addable+0x4d/0xf0 md_spares_need_change in md_start_sync will call rdev_addable which protected by rcu_read_lock/rcu_read_unlock. This rcu context will help protect rdev won't be released, but rdev->mddev will be set to NULL before we call synchronize_rcu in md_kick_rdev_from_array. Fix this by using READ_ONCE and check does rdev->mddev still alive.

References

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