CVE intelligenceCISA KEV

CVE-2026-46300

Linux Kernel Missing Initialization of a Variable Vulnerability

Published May 23, 2026Sources checked Nov 12, 2026

7.8HIGHCVSS out of 10

What this means

Actively exploited

CISA lists CVE-2026-46300 in its Known Exploited Vulnerabilities catalog, which means exploitation has been observed. The entry applies to Linux Kernel.

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Public exploit: Cataloged public exploit.

Rapid7 Metasploit: Fragnesia LPE (CVE-2026-46300) (2026-09-23 21:40:29.350562+00)
Rapid7 catalogs an exploit module for this CVE. Module availability does not establish exploitation in the wild or applicability to your environment.
Exploit-DB: Linux Kernel - Local Privilege Escalation (2026-09-23 21:40:27.335989+00)
Exploit-DB lists a public exploit or proof of concept for this CVE. SecurityAlert has not executed it; this is not evidence of attacks against your systems.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Jun 9, 2026

CBL-Mariner Releases

Vendor-listed releases

6.6.141.1-1

CISA KEVListedObserved exploitation

EPSS16.1%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors1Source-linked actor relationships

Overview

What is CVE-2026-46300?

In the Linux kernel, the following vulnerability has been resolved:

net: skbuff: preserve shared-frag marker during coalescing

skb_try_coalesce() can attach paged frags from @from to @to. If @from has SKBFL_SHARED_FRAG set, the resulting @to skb can contain the same externally-owned or page-cache-backed frags, but the shared-frag marker is currently lost.

That breaks the invariant relied on by later in-place writers. In particular, ESP input checks skb_has_shared_frag() before deciding whether an uncloned nonlinear skb can skip skb_cow_data().

If TCP receive coalescing has moved shared frags into an unmarked skb, ESP can see skb_has_shared_frag() as false and decrypt in place over page-cache backed frags.

Propagate SKBFL_SHARED_FRAG when skb_try_coalesce() transfers paged frags. The tailroom copy path does not need the marker because it copies bytes into @to's linear data rather than transferring frag descriptors.

Source: NVD

CISA says:Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.CISA catalog due date Oct 31, 2026