What is CVE-2026-89657?

CVE-2026-89657 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10, affecting Linux kernel versions from 6.6 onward and patched in 6.6.157, 6.12.109, 6.18.50 and others. CVE-2026-89657 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-89657?

CVE-2026-89657 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-2026-89657?

Yes, CVE-2026-89657 has been patched. Fixed versions include 6.6.157, 6.12.109, 6.18.50 and others. If you are running Linux kernel 6.6 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-89657 actively exploited?

CVE-2026-89657 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-89657

High

In the Linux kernel, the following vulnerability has been resolved: libceph: validate OSD extent maps before cursor advance net/ceph/osd_client.c:osd_sparse_read() validates that the sparse-read data length matches the summed extent lengths, but it does not validate that each OSD-supplied extent is monotonic and lies inside the original request range. A malformed authenticated OSD reply can advertise a far-forward nonzero extent offset with a matching data length and make the client advance the message-data cursor beyond the request buffer. This reaches the BUG_ON(!*length) assertion in ceph_msg_data_next() from the client receive path. Impact: A malicious or compromised authenticated Ceph OSD peer can crash a kernel Ceph client via a malformed sparse-read reply. Reject sparse extent maps that overflow, move backwards, overlap, or extend outside the original sparse-read request before advancing the cursor. [ idryomov: perform sparse_extent_map_valid() check a bit earlier, in CEPH_SPARSE_READ_DATA_LEN instead of CEPH_SPARSE_READ_DATA_PRE state ]

Package Linux Kernel

Published 2026-09-11

Last modified 2026-09-14

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 6.6 and later are affected. Fixed in 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3-rc1 and their respective stable series.

Affected from

≥ 6.6

Fixed in

✓ 6.6.157 6.6.x ✓ 6.12.109 6.12.x ✓ 6.18.50 6.18.x ✓ 7.2.4 7.2.x ✓ 7.3-rc1

References

5 total

Details

CVE ID CVE-2026-89657

Severity High

CVSS score 7.5 / 10

CVSS version 3.1

Published 2026-09-11

Modified 2026-09-14

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-89657?

CVE-2026-89657 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10 . It affects Linux kernel versions from 6.6 onward and has been patched in 6.6.157, 6.12.109, 6.18.50 and others. CVE-2026-89657 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-89657?

CVE-2026-89657 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-2026-89657?

Yes. CVE-2026-89657 has been patched. Fixed versions include 6.6.157, 6.12.109, 6.18.50 and others. If you are running Linux kernel 6.6 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-89657 actively exploited?

No. CVE-2026-89657 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.