CVE-2026-89676
What it is
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix stale s2s_cp_stateids IDR entry for async COPY For an async COPY, nfsd4_copy() called nfs4_init_copy_state() before dup_copy_fields(), so the s2s_cp_stateids IDR was pointed at &u->copy->cp_stateid -- memory in the per-rqstp COMPOUND buffer that is reused by the next request. dup_copy_fields() copies only the value into async_copy, so the IDR slot dangled at the transient buffer for the whole background copy. Any IDR walker then dereferences reused request memory: the laundromat reads cs_type from it and, if the bytes look like an expired NFS4_COPYNOTIFY_STID, follows into refcount_dec()/idr_remove()/kfree() on garbage; manage_cpntf_state() has the same exposure via idr_find(). Duplicate the fields first, then register the stateid on the stable async_copy. result->cb_stateid is unchanged.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.5% chance of exploitation in the next 30 days (EPSS).
- Fix
- No patch or advisory is linked yet. Look at mitigations or restrict exposure.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.5% in the next 30 days (EPSS).
- Severity: 9.8 CRITICAL (CVSS).
- Fix: none linked yet, which raises it.
Details
- Published
- Last modified
- Exploit probability
- 0.5% · EPSS, next 30 days
- Record status
- Received
Attack profile CVSS 3.1 · 9.8
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-89676.md and follow it. Check whether this project is affected by CVE-2026-89676. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
References
- https://git.kernel.org/stable/c/14b978e8d05ce018d0afbeb6611833ef91713a02
- https://git.kernel.org/stable/c/745b2edfdd96b8738a94dee450adff4c7d026d5b
- https://git.kernel.org/stable/c/7aa34ea78f74e6ef60c8112635a87fc43d57f6c9
- https://git.kernel.org/stable/c/9b4e5e9ba5ae13808b8a6d229d87c54611ba0e7a
- https://git.kernel.org/stable/c/bdce362f49410b9def65d76c21f6259cd89696d8
- https://git.kernel.org/stable/c/d0beaee498e11880e72826026db0e9c9890fc114