VULNpocalypse

CVE-2026-46300: Linux Kernel Missing Initialization of a Variable Vulnerability

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

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.

Description quoted from the CVE record (assigned by Linux, published 2026-05-23).

Weakness: Write-what-where Condition; CWE-456 Missing Initialization of a Variable

How it can be exploited

Exploitable with local access with low attack complexity needing low privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: no. Technical impact: total.

On CISA KEV since
2026-10-28
US federal deadline
2026-10-31
Ransomware use
Not known

Public exploit evidence (Exploit Observer)

Also known as: BDU:2026-06785, CNVD-2026-21361, EDB-52591, EUVD-2026-31535, EUVD-2026-42870, GHSA-47jg-vqrv-5f8v, GHSA-7xf9-r6gc-x4cm

VEDAS cluster: VEDAS:AVALANCHEARROW

Exploit Observer links 14 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (14)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Research and write-ups (7)

Vulnerability databases and vendor advisories (17)

Catalogue entries, not exploit evidence.

News (1)

284 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS
0.161
likely to be attacked soon
VEDAS
0.977
strong exploit evidence
On CISA KEV
Yes, since 2026-10-28
Detection rule
Out of scope (local)
EPSS (chance of attack)
100.1Added to CISA KEV 2026-10-28CVE-2026-46300 EPSS over time2026-082026-11-01
VEDAS (exploit evidence)
100.9Added to CISA KEV 2026-10-28CVE-2026-46300 VEDAS over time2026-082026-11-01

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.

VEDAS flagged this bug about 81 days before CISA confirmed attacks.

Who is affected

ProductAffectedNot affected
Linux Linuxfrom cef401de7be8 before 3599e6b3cc1a (git commit)
from cef401de7be8 before 2f2b16022a2e (git commit)
from cef401de7be8 before 9d3e5fd19fe1 (git commit)
from cef401de7be8 before 78bf6b6bb195 (git commit)
from cef401de7be8 before 760e1addc27b (git commit)
from cef401de7be8 before 3bd9e113d500 (git commit)
from cef401de7be8 before 3884358a9286 (git commit)
from cef401de7be8 before f84eca581739 (git commit)		Not stated
Linux Linuxversion 3.90 is not affected (up to 3.9); 5.10.257 is not affected; 5.15.208 is not affected; 6.1.174 is not affected

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: linux linux_kernel, redhat enterprise_linux, redhat enterprise_linux_aus, redhat enterprise_linux_eus, redhat enterprise_linux_tus, redhat enterprise_linux_update_services_for_sap_solutions.

How to fix it

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.

Vendor guidance:

25 more

How to detect it

This bug needs local access to exploit. VEDAS signatures cover remotely exploitable bugs for now, so there is no network rule or remote check for it. Patch it and watch your endpoint telemetry for unusual local activity.

Advisories on this CVE

References

Vendor advisories and patches

21 more

Exploits and technical analysis

Government sources

Other references

4 more

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.