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CVE-2026-89805 high CVSS 7.8

Vulnerability in Linux kernel (CVE-2026-89805)

Summary

Vulnerability in Linux kernel (CVE-2026-89805). Successful exploitation can lead to full system takeover.

Original description

The description as published by the source.

In the Linux kernel, the following vulnerability has been resolved:

drm/pagemap: Fix folio allocation fallback and use-after-put

drm_pagemap_migrate_populate_ram_pfn() had two issues when populating
RAM PFNs with higher-order folios:

  1. The higher-order vma_alloc_folio()/folio_alloc() calls did not pass
    __GFP_NOWARN, so a THP allocation failure under memory pressure
    would spam the kernel log, and there was no fallback path despite a
    TODO comment stating one was needed. Add __GFP_NOWARN to the
    higher-order allocation and, on failure, fall back to order-0
    allocations for the entire range originally covered by the failed
    higher-order allocation, leaving MIGRATE_PFN_COMPOUND unset for
    those PFNs.

  2. In the free_pages error path, order was computed via
    folio_order(page_folio(page)) after put_page(page) had already
    dropped the reference, resulting in a use-after-free/put when that
    was the last reference on the page. Compute order before releasing
    the page.

Introducing the fallback in 1. also requires the source page array
handed to ->copy_to_ram() to be built differently. Both callers only
populated the entry at the head of each source folio, relying on the
copy callback to derive the rest of the folio from the order recorded
in the matching drm_pagemap_addr. Once the destination has been demoted
to order-0 folios the drm_pagemap_addr entries are per-page, so a source
page is needed for every one of them; leaving them NULL makes the copy
call…

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-89805 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-89805" on the vendor's site.

CVE-2026-89805 (Linux kernel) — CVSS v3 7.8
Attack vector: local / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in Linux kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel.

🔥 Severity

Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    Audit SBOM/dependencies for affected components.

    資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。

  2. 2
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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