CVE entry · CVE-2026-46300
CVE-2026-46300: Linux Kernel Missing Initialization of a Variable Vulnerability
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.
- Actively exploited: added to CISA’s KEV catalog on October 28, 2026.
- Use by ransomware: not established so far.
- Remediation deadline for US federal agencies: October 31, 2026.
Description from CISA’s KEV catalog.
What to do
- Check whether your estate includes Linux Kernel, including internet-facing devices.
- Apply the vendor’s patch or mitigations (references below). Failing that, isolate the product or stop using it, as CISA requires of US federal agencies.
- An exploited vulnerability has often been used before it was fixed: look for signs of compromise, especially on internet-facing devices.
References
- Vendor advisory or reference cited by CISA (git.kernel.org)
- Vendor advisory or reference cited by CISA (git.kernel.org)
- Vendor advisory or reference cited by CISA (git.kernel.org)
- Vendor advisory or reference cited by CISA (git.kernel.org)
- Vendor advisory or reference cited by CISA (git.kernel.org)
- Vendor advisory or reference cited by CISA (git.kernel.org)
- Vendor advisory or reference cited by CISA (git.kernel.org)
- Vendor advisory or reference cited by CISA (git.kernel.org)
- NVD entry (NIST)
- CISA KEV catalog
Other Linux vulnerabilities
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Linux Kernel Out-of-Bounds Write Vulnerability
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Linux Kernel Race Condition Vulnerability
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Linux Kernel Improper Check for Unusual or Exceptional Conditions Vulnerability
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Linux Kernel Unspecified Vulnerability
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Linux Kernel Out-of-Bounds Write Vulnerability
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Linux Kernel Improper Authentication Vulnerability