CVE-2026-46300

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.

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

• 7.8CVSS 3.1, Highfrom the CNA (Linux)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• 7.8CVSS 3.1, Highfrom redhat-SADP (ADP container)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

What to do

• 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 KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

Timeline

1. 23 May 2026 Published
2. 28 Oct 2026 CVE-2026-46300 added to CISA KEV
3. 28 Oct 2026 Added to the CISA KEV catalogue

Weakness

• CWE-456

Related coverage

• CISA warns Fragnesia Linux flaw is being chained with PHP2Shell bugs29 Oct 2026
• Linux kernel flaw can be chained with two PHP bugs to plant webshells, NVD entry says28 Oct 2026

References

• git.kernel.org
• git.kernel.org
• git.kernel.org
• git.kernel.org
• git.kernel.org
• git.kernel.org
• git.kernel.org
• git.kernel.org