Exploited vulnerabilities / CVE-2026-46300
Confirmed exploited · exploited vulnerability · Linux KernelCVE-2026-46300
Linux Kernel exploited vulnerability, confirmed exploited in the wild.
Linux Kernel contains a missing initialization of a variable vulnerability that could allow for unintended modification of page-cache-backed data via failure to preserve the shared-fragment marker during socket buffer coalescing, causing ESP input processing to decrypt shared fragments in place. This vulnerability can be chained with CVE-2026-109618 and CVE-2026-109619 to implant PHP webshells and run commands as root.
| CISA's name for it | Linux Kernel Missing Initialization of a Variable Vulnerability |
|---|---|
| Vendor and product | Linux · Kernel |
| Type | exploited vulnerability · CWE-456 |
| Exploited | Confirmed by CISA listed 28 October 2026 |
| Likelihood | one of the most likely to be exploited of every vulnerability tracked |
| Deadline | 31 October 2026 · already passed |
| Used in ransomware | Not reported |
| Advisories | git.kernel.org ↗ · git.kernel.org ↗ · git.kernel.org ↗ · git.kernel.org ↗ |
Three steps, in this order
Apply the vendor's fix or mitigation; CISA lists only vulnerabilities seen exploited.
If you cannot patch now, restrict network access to the affected product.
Check for signs of compromise since the date it was added to the list.
| CISA's 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. |
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Know before someone else finds it
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CVE-2026-46300 in short
Is CVE-2026-46300 being exploited?
Yes. CISA added CVE-2026-46300 to its Known Exploited Vulnerabilities catalogue on 28 October 2026, which it does only on evidence of exploitation in the wild.
What is the CISA deadline for CVE-2026-46300?
US federal agencies must remediate it by 31 October 2026. Everyone else should treat that date as the latest safe point to patch an internet-facing system.
How likely is CVE-2026-46300 to be exploited in the next 30 days?
FIRST's Exploit Prediction Scoring System gives it 16%, the 96th percentile of every CVE it scores.
How do I fix CVE-2026-46300?
Apply the vendor's fix or mitigation; CISA lists only vulnerabilities seen exploited. If you cannot patch now, restrict network access to the affected product. Check for signs of compromise since the date it was added to the list.
Other Linux vulnerabilities being exploited
| CVE | Product | Type | Listed |
|---|---|---|---|
| CVE-2025-39964 | Kernel | exploited vulnerability | 18 September 2026 |
| CVE-2026-53266 | Kernel | memory corruption | 18 September 2026 |
| CVE-2025-39682 | Kernel | exploited vulnerability | 18 September 2026 |
| CVE-2026-53362 | Kernel | privilege escalation | 27 August 2026 |
| CVE-2022-0995 | Kernel | privilege escalation | 26 August 2026 |
| CVE-2022-0492 | Kernel | authentication bypass | 2 June 2026 |
Sources: CISA Known Exploited Vulnerabilities catalogue (released 10 November 2026) and FIRST EPSS. Page compiled automatically by SAK T.L.M, the threat-intelligence tool of SAK T.E.C, on 13 November 2026.