CVE-2026-89699
Published: September 15, 2026Last modified: September 28, 2026
Description
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.5 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Vulnerable (6.1.182-r0) |
| 25 LTS | linux-lts | Fixed (6.12.111-r0) | |
| Stream | linux-lts | Fixed (6.18.53-r0) |
References
- https://git.kernel.org/stable/c/041f57056e5fb9c80adc088269322d2c61074406
- https://git.kernel.org/stable/c/36011308b3f01ce7dc9954f3cefcbb5291af9f95
- https://git.kernel.org/stable/c/3ef5e7a01a4d74995a65496bc9166d1e980a4355
- https://git.kernel.org/stable/c/45ec115cbfecb4b3cfab7fca6f73d1b60696a25a
- https://git.kernel.org/stable/c/8661d3cb38fd148947e57dbc0871fd4d3fa33bbf
- https://git.kernel.org/stable/c/888dad4b557352cf85be31613407b5ba51ad07d1
- https://git.kernel.org/stable/c/895a485cd3758031ef9993c0d53cf19ce8fb4ccc
- https://git.kernel.org/stable/c/b24843ea3de1676b29902457b38507c95a80649b