What is CVE-2026-64566?

CVE-2026-64566 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, affecting Linux kernel versions from 6.14 onward and patched in 6.18.42, 7.1.6 and 7.2. CVE-2026-64566 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-64566?

CVE-2026-64566 has a CVSS score of 9.8 out of 10, rated Critical severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-64566?

Yes, CVE-2026-64566 has been patched. Fixed versions include 6.18.42, 7.1.6 and 7.2. If you are running Linux kernel 6.14 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-64566 actively exploited?

CVE-2026-64566 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-64566

Critical

In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags() When iptfs_skb_add_frags() copies frag references from the source frag walk into a new SKB, it increments the page reference count via __skb_frag_ref() but does not propagate SKBFL_SHARED_FRAG to the destination SKB's skb_shinfo->flags. If the source SKB carries shared frags (e.g. from a page-pool backed receive path), the new inner SKB will appear to ESP as having privately owned frags. A subsequent esp_input() call for a nested transport-mode SA then takes the no-COW fast path and decrypts in place, writing over pages that are still referenced by the outer IPTFS SKB. This causes kernel-visible memory corruption and can trigger a panic. All other frag-transfer helpers in the kernel (skb_try_coalesce, skb_gro_receive, __pskb_copy_fclone, skb_shift, skb_segment) correctly propagate SKBFL_SHARED_FRAG; align iptfs_skb_add_frags() with this convention by setting the flag inside the loop immediately after __skb_frag_ref() and nr_frags++, so every exit path that attaches a frag unconditionally propagates SKBFL_SHARED_FRAG.

Package Linux Kernel

Published 2026-08-05

Last modified 2026-08-17

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.8

out of 10

Critical

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Affected versions

Linux kernel versions 6.14 and later are affected. Fixed in 6.18.42, 7.1.6, 7.2 and their respective stable series.

Affected from

≥ 6.14

Fixed in

✓ 6.18.42 6.18.x ✓ 7.1.6 7.1.x ✓ 7.2

References

3 total

Details

CVE ID CVE-2026-64566

Severity Critical

CVSS score 9.8 / 10

CVSS version 3.1

Published 2026-08-05

Modified 2026-08-17

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-64566?

CVE-2026-64566 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 . It affects Linux kernel versions from 6.14 onward and has been patched in 6.18.42, 7.1.6 and 7.2. CVE-2026-64566 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-64566?

CVE-2026-64566 has a CVSS score of 9.8 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:H/I:H/A:H.
Is there a patch available for CVE-2026-64566?

Yes. CVE-2026-64566 has been patched. Fixed versions include 6.18.42, 7.1.6 and 7.2. If you are running Linux kernel 6.14 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-64566 actively exploited?

No. CVE-2026-64566 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.