Intelligence online17 sources monitored12 actively exploited 7d34 published 24hChecked recently
Vulnerability record

CVE-2026-46300

Linux Kernel Missing Initialization of a Variable Vulnerability

HighExploitation confirmedCISA KEV
What should I do?

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it. If you run Linux, fix it now.

CISA required action: 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.

US federal civilian agencies must remediate by Oct 31, 2026.

Patch status

Official fix available since

Apply the vendor's update to every affected system. Check the fixed-in versions below where known.

Basis: NVD patch reference

Description

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: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.

Affected products

ProductVendorAffected versionsFixed inSource
LinuxLinux>= 3.9, <= 5.10.257; >= 5.11, < 5.15.208; >= 5.16, < 6.1.174; >= 6.2, < 6.6.141; >= 6.7, < 6.12.91; >= 6.13, < 6.18.335.15.208; 6.1.174; 6.6.141; 6.12.91; 6.18.33; 7.0.10KEV

Sources: KEV = CISA Known Exploited Vulnerabilities catalog.

Intelligence timeline

Developments from the last 30 days, newest first.

  1. CVSS scoredUpdateKEV

    CVE-2026-46300 scored CVSS 7.8: Linux Kernel, Linux Kernel Missing Initialization of a Variable Vulnerability

    CISA lists this as exploited in the wild. Unpatched Kernel systems are exposed to active attacks now.

    Basis: NIST National Vulnerability Database

  2. Patch releasedUpdateKEV

    Patch released for CVE-2026-46300: Linux Kernel, Linux Kernel Missing Initialization of a Variable Vulnerability

    An official fix is now available for Linux Kernel. This vulnerability is being exploited, so apply it promptly.

    Basis: NVD patch reference

  3. Added to CISA KEV

    CVE-2026-46300 added to CISA KEV: Linux Kernel, Linux Kernel Missing Initialization of a Variable Vulnerability

    CISA lists this as exploited in the wild. Unpatched Kernel systems are exposed to active attacks now.

    Basis: CISA Known Exploited Vulnerabilities catalog

Coverage

We have not published a story about this vulnerability yet.

References