What is CVE-2026-89713?

CVE-2026-89713 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.1 out of 10, affecting Linux kernel versions from 3.2.89 onward and patched in 6.12.109, 6.18.50, 7.2.4 and others. CVE-2026-89713 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-89713?

CVE-2026-89713 has a CVSS score of 9.1 out of 10, rated Critical severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.

Is there a patch available for CVE-2026-89713?

Yes, CVE-2026-89713 has been patched. Fixed versions include 6.12.109, 6.18.50, 7.2.4 and others. If you are running Linux kernel 3.2.89 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-89713 actively exploited?

CVE-2026-89713 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-89713

Critical

In the Linux kernel, the following vulnerability has been resolved: NFSD: check truncate permission under inode lock nfsd_setattr() checks whether a size update needs NFSD_MAY_TRUNC before it takes inode_lock(). The comparison uses the file size sampled by that unlocked read, but the actual ATTR_SIZE update is applied later under inode_lock() by notify_change(). This leaves a TOCTOU window for append-only files. If a client sends a SETATTR that does not shrink the file at the time of the unlocked sample, a concurrent append can extend the file before nfsd_setattr() takes inode_lock(). notify_change() then applies a real truncation without the NFSD_MAY_TRUNC check that rejects IS_APPEND(inode). The VFS truncate syscall paths perform their own append-only checks before calling notify_change(), so NFSD must make this decision against the locked size it is about to change. Split the write-count acquisition from the truncation permission check. Keep get_write_access() before the locked setattr work, then recheck whether the requested size is below i_size_read(inode) after inode_lock() has been acquired and before notify_change(ATTR_SIZE). This also avoids the plain unlocked inode->i_size load.

Package Linux Kernel

Published 2026-09-11

Last modified 2026-09-13

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.1

out of 10

Critical

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

High

Availability

High

Vector string

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

Affected versions

Linux kernel versions 3.2.89, 3.16.44, 4.4.53, 4.9.14, 4.10.2, 4.11 and later are affected. Fixed in 6.12.109, 6.18.50, 7.2.4, 7.3-rc1 and their respective stable series.

Affected from

≥ 3.2.89 ≥ 3.16.44 ≥ 4.4.53 ≥ 4.9.14 ≥ 4.10.2 ≥ 4.11

Fixed in

✓ 6.12.109 6.12.x ✓ 6.18.50 6.18.x ✓ 7.2.4 7.2.x ✓ 7.3-rc1

References

4 total

Details

CVE ID CVE-2026-89713

Severity Critical

CVSS score 9.1 / 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-2026-89713?

CVE-2026-89713 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.1 out of 10 . It affects Linux kernel versions from 3.2.89 onward and has been patched in 6.12.109, 6.18.50, 7.2.4 and others. CVE-2026-89713 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-89713?

CVE-2026-89713 has a CVSS score of 9.1 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.
Is there a patch available for CVE-2026-89713?

Yes. CVE-2026-89713 has been patched. Fixed versions include 6.12.109, 6.18.50, 7.2.4 and others. If you are running Linux kernel 3.2.89 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-89713 actively exploited?

No. CVE-2026-89713 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.