nfsd: validate symlink target length in NFSv4 CREATE
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 7 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: validate symlink target length in NFSv4 CREATE nfsd4_decode_create() accepts an unbounded cr_datalen from the wire for NF4LNK symlink targets, allowing a client to force a kmalloc of up to the maximum RPC payload size (several MiB) per COMPOUND op that persists until compound teardown. The VFS rejects oversized targets with ENAMETOOLONG, but the allocation has already occurred. Reject cr_datalen == 0 early with nfserr_inval and cr_datalen greater than NFS4_MAXPATHLEN (PATH_MAX) with nfserr_nametoolong to bound the allocation.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.12 and later | 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.12 and later Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-89699
- 2026-10-03 Alias added: GHSA-864v-pq9r-vg9w
- 2026-10-05 EPSS moved to the below the 50th percentile
- 2026-10-18 CISA SSVC decision points changed
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/36011308b3f01ce7dc9954f3cefcbb5291af9f95
- https://git.kernel.org/stable/c/888dad4b557352cf85be31613407b5ba51ad07d1
- https://git.kernel.org/stable/c/8661d3cb38fd148947e57dbc0871fd4d3fa33bbf
- https://git.kernel.org/stable/c/3ef5e7a01a4d74995a65496bc9166d1e980a4355
- https://git.kernel.org/stable/c/b24843ea3de1676b29902457b38507c95a80649b
- https://git.kernel.org/stable/c/895a485cd3758031ef9993c0d53cf19ce8fb4ccc
- https://git.kernel.org/stable/c/45ec115cbfecb4b3cfab7fca6f73d1b60696a25a
- https://git.kernel.org/stable/c/041f57056e5fb9c80adc088269322d2c61074406
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- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
Sources
- CVE-2026-89699 · CVE Program
- CVE-2026-89699 · NVD
- FIRST EPSS
- GHSA-864v-pq9r-vg9w · GitHub Advisory Database · CC BY 4.0
- CVE-2026-89699 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences