What is CVE-2026-63912?

CVE-2026-63912 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, affecting Linux kernel versions from 5.10.113 onward and patched in 5.10.259, 5.15.210, 6.1.176 and others. CVE-2026-63912 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-63912?

CVE-2026-63912 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-2026-63912?

Yes, CVE-2026-63912 has been patched. Fixed versions include 5.10.259, 5.15.210, 6.1.176 and others. If you are running Linux kernel 5.10.113 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-63912 actively exploited?

CVE-2026-63912 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-63912

Critical

In the Linux kernel, the following vulnerability has been resolved: xfrm: esp: restore combined single-frag length gate The ESP out-of-place fast path appends the trailer in esp_output_head() before esp_output_tail() allocates the destination page frag. The head-side gate currently checks skb->data_len and tailen separately, but the tail code allocates a single destination frag from the combined post-trailer skb->data_len. Reject the page-frag fast path when the combined aligned length exceeds a page. Otherwise skb_page_frag_refill() may fall back to a single page while the destination sg still spans the combined skb->data_len. Restore this combined-length page gate for both IPv4 and IPv6.

Package Linux Kernel

Published 2026-07-19

Last modified 2026-07-27

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 5.10.113, 5.15.36, 4.14.288, 4.19.252, 5.4.205, 5.17.5, 5.18 and later are affected. Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1 and their respective stable series.

Affected from

≥ 5.10.113 ≥ 5.15.36 ≥ 4.14.288 ≥ 4.19.252 ≥ 5.4.205 ≥ 5.17.5 ≥ 5.18

Fixed in

✓ 5.10.259 5.10.x ✓ 5.15.210 5.15.x ✓ 6.1.176 6.1.x ✓ 6.6.143 6.6.x ✓ 6.12.93 6.12.x ✓ 6.18.35 6.18.x ✓ 7.0.12 7.0.x ✓ 7.1

References

8 total

Showing 5 of 8 references View all on NVD

Details

CVE ID CVE-2026-63912

Severity Critical

CVSS score 9.8 / 10

CVSS version 3.1

Published 2026-07-19

Modified 2026-07-27

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-63912?

CVE-2026-63912 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 . It affects Linux kernel versions from 5.10.113 onward and has been patched in 5.10.259, 5.15.210, 6.1.176 and others. CVE-2026-63912 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-63912?

CVE-2026-63912 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-2026-63912?

Yes. CVE-2026-63912 has been patched. Fixed versions include 5.10.259, 5.15.210, 6.1.176 and others. If you are running Linux kernel 5.10.113 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-63912 actively exploited?

No. CVE-2026-63912 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.