# CVE-2026-89695: linux: In the Linux kernel, the following vulnerability has been resolved:  nfsd: cap decoded POSIX ACL count to bound sort...

CVE-2026-89695 is fixed in linux on 1 platform by DEBIAN-CVE-2026-89695 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-89695
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0049
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 11, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  nfsd: cap decoded POSIX ACL count to bound sort cost  nfsd4_decode_posixacl() reads a u32 entry count off the wire and passes it straight to posix_acl_alloc() and sort_pacl_range(). The latter is an O(n^2) bubble sort, so a client-chosen count drives unbounded CPU in the server's compound processing path.      nfsd4_decode_posixacl()       xdr_stream_decode_u32(&count)       /* uncapped u32 */       posix_acl_alloc(count, GFP_KERNEL)       sort_pacl_range(*acl, 0, count - 1) /* O(n^2) bubble sort */  The encoder side in the same file already rejects ACLs whose a_count exceeds NFS_ACL_MAX_ENTRIES, but the decoder introduced in commit 5fc51dfc2eb1 ("NFSD: Add support for XDR decoding POSIX draft ACLs") omitted the symmetric check.  Fix by rejecting a wire count greater than NFS_ACL_MAX_ENTRIES with nfserr_inval, before any allocation, so the sort is bounded by NFS_ACL_MAX_ENTRIES^2 comparisons.  While we're in here, also fix the nfserr_resource return if posix_acl_alloc() fails. That's not a legal error code for v4.1+. Change it to return nfserr_jukebox as that's more appropriate for memory allocation failures.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-89695](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89695.md) | Sep 23, 2026 |

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