CVE-2026-46300

HIGH7.8

CISA KEV

Published 2026-05-23 · Updated 2026-10-28 · Source 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Summary

CVE-2026-46300 is a high-severity (CVSS 7.8) vulnerability in Linux Kernel. CISA added it to the Known Exploited Vulnerabilities catalog on October 28, 2026, which means exploitation in the wild has been confirmed; US federal agencies must remediate it by October 31, 2026. CISA does not currently list it as used in ransomware campaigns. Linux has 32 vulnerabilities in the KEV catalog, 2 of them linked to ransomware.

All 32 known-exploited Linux vulnerabilities →

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.

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

CWE-787CWE-456CWE-123

CISA Known-Exploited Vulnerability

Product: Linux — Kernel

Name: Linux Kernel Missing Initialization of a Variable Vulnerability

Date added: 2026-10-28 · Due: 2026-10-31

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.

References

View on NVD

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added 2026-08-27
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Kernel — Linux Kernel Out-of-Bounds Write Vulnerability
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CVE-2022-0492
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added 2026-06-02

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