CVE-2026-46300

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.

In the wild

CISA lists this as exploited in real attacks. Treat as urgent.

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-13 15:03 UTC ReservedThe CVE id was reserved by its CNA
2. 2026-05-23 12:17 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2026-10-28 Exploited in the wildAdded to CISA's Known Exploited Vulnerabilities list
4. 2026-10-29 17:30 UTC Last updatedMost recent change to the record
5. 2026-10-31 Remediation deadlineCISA's due date for federal agencies to fix it

Why it ranks here

• Exploited in the wild: yes, CISA lists it. This puts it above everything that is not.
• Exploit odds: 16.1% in the next 30 days (EPSS).
• Severity: 7.8 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-05-23 12:17 UTC

Last modified

2026-10-29 17:30 UTC

Added to CISA KEV

2026-10-28

Exploit probability

16.1% · EPSS, next 30 days

Weakness

CWE-787 · Out-of-bounds write

Record status

Analyzed

Affected

• Linux Kernel ≤ 5.10.257
• Linux Kernel < 5.15.208
• Linux Kernel < 6.1.174
• Linux Kernel < 6.6.141
• Linux Kernel < 6.12.91
• Linux Kernel < 6.18.33
• Linux Kernel < 7.0.10
• Linux Kernel 7.1

Attack profile CVSS 3.1 · 7.8

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-46300.md and follow it. Check whether this project is affected by CVE-2026-46300. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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