What is CVE-2026-89695?

CVE-2026-89695 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10, affecting Linux kernel versions from 7.0 onward and patched in 7.2.4 and 7.3-rc1. CVE-2026-89695 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-89695?

CVE-2026-89695 has a CVSS score of 7.5 out of 10, rated High severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2026-89695?

Yes, CVE-2026-89695 has been patched. Fixed versions include 7.2.4 and 7.3-rc1. If you are running Linux kernel 7.0 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-89695 actively exploited?

CVE-2026-89695 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-89695

High

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.

Package Linux Kernel

Published 2026-09-11

Last modified 2026-09-13

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.5

out of 10

High

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected versions

Linux kernel versions 7.0 and later are affected. Fixed in 7.2.4, 7.3-rc1 and their respective stable series.

Affected from

≥ 7.0

Fixed in

✓ 7.2.4 7.2.x ✓ 7.3-rc1

References

2 total

Details

CVE ID CVE-2026-89695

Severity High

CVSS score 7.5 / 10

CVSS version 3.1

Published 2026-09-11

Modified 2026-09-13

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-89695?

CVE-2026-89695 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10 . It affects Linux kernel versions from 7.0 onward and has been patched in 7.2.4 and 7.3-rc1. CVE-2026-89695 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-89695?

CVE-2026-89695 has a CVSS score of 7.5 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2026-89695?

Yes. CVE-2026-89695 has been patched. Fixed versions include 7.2.4 and 7.3-rc1. If you are running Linux kernel 7.0 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-89695 actively exploited?

No. CVE-2026-89695 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.