What is CVE-2026-99056?

CVE-2026-99056 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10, affecting Linux kernel versions from 5.6 onward and patched in 6.6.160, 6.12.113, 6.18.57 and others. CVE-2026-99056 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-99056?

CVE-2026-99056 has a CVSS score of 7.8 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-99056?

Yes, CVE-2026-99056 has been patched. Fixed versions include 6.6.160, 6.12.113, 6.18.57 and others. If you are running Linux kernel 5.6 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-99056 actively exploited?

CVE-2026-99056 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-99056

High

In the Linux kernel, the following vulnerability has been resolved: strparser: make sure __strp_recv isn't running before tearing down the parser The comment above strp_done() claims that if strp is stopped, strp_recv will no longer be called. That's only true if the caller has a mechanism (eg locking) to guarantee that strp_recv() calls that started before strp_stop() have completed by the time we call strp_done(). This adds a dummy lock_sock/release_sock pair to guarantee that any in-flight strp_recv() (which runs under either bh_lock_sock or lock_sock, depending if it's called from ->sk_data_ready or strp_work) has completed. Only espintcp can be affected by this race condition, but this patch makes sure no future user of strp can have the bug. This could crash on strp->sk ("general mode" of strp), but this mode has been here for 9 years and has never been used. It'll be gone soon, no point worrying about it. Switch the stopped/paused/etc bits to u8's to avoid races between strp_stop() and strp_pause/unpause(). A reproducer has been published and turns the possible UAF into an exploit [1].

Package Linux Kernel

Published 2026-10-23

Last modified 2026-10-24

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.8

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Affected versions

Linux kernel versions 5.6 and later are affected. Fixed in 6.6.160, 6.12.113, 6.18.57, 7.2.11, 7.3 and their respective stable series.

Affected from

≥ 5.6

Fixed in

✓ 6.6.160 6.6.x ✓ 6.12.113 6.12.x ✓ 6.18.57 6.18.x ✓ 7.2.11 7.2.x ✓ 7.3

References

5 total

Details

CVE ID CVE-2026-99056

Severity High

CVSS score 7.8 / 10

CVSS version 3.1

Published 2026-10-23

Modified 2026-10-24

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-99056?

CVE-2026-99056 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 5.6 onward and has been patched in 6.6.160, 6.12.113, 6.18.57 and others. CVE-2026-99056 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-99056?

CVE-2026-99056 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-99056?

Yes. CVE-2026-99056 has been patched. Fixed versions include 6.6.160, 6.12.113, 6.18.57 and others. If you are running Linux kernel 5.6 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-99056 actively exploited?

No. CVE-2026-99056 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.