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CVE-2026-45984 high CVSS 7.8

Use-After-Free in Linux kernel (CVE-2026-45984)

Summary

Vulnerability in Linux kernel (CVE-2026-45984). 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:

gfs2: Fix use-after-free in iomap inline data write path

The inline data buffer head (dibh) is being released prematurely in
gfs2_iomap_begin() via release_metapath() while iomap->inline_data
still points to dibh->b_data. This causes a use-after-free when
iomap_write_end_inline() later attempts to write to the inline data
area.

The bug sequence:

  1. gfs2_iomap_begin() calls gfs2_meta_inode_buffer() to read inode
    metadata into dibh
  2. Sets iomap->inline_data = dibh->b_data + sizeof(struct gfs2_dinode)
  3. Calls release_metapath() which calls brelse(dibh), dropping refcount
    to 0
  4. kswapd reclaims the page (~39ms later in the syzbot report)
  5. iomap_write_end_inline() tries to memcpy() to iomap->inline_data
  6. KASAN detects use-after-free write to freed memory

Fix by storing dibh in iomap->private and incrementing its refcount
with get_bh() in gfs2_iomap_begin(). The buffer is then properly
released in gfs2_iomap_end() after the inline write completes,
ensuring the page stays alive for the entire iomap operation.

Note: A C reproducer is not available for this issue. The fix is based
on analysis of the KASAN report and code review showing the buffer head
is freed before use.

[agruenba: Take buffer head reference in gfs2_iomap_begin() to avoid
leaks in gfs2_iomap_get() and gfs2_iomap_alloc().]

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-2026-45984 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-2026-45984" on the vendor's site.

CVE-2026-45984 (Linux kernel) — CWE-416 / 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

Use-after-free (CWE-416) 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。

Affected packages

Linux Kernel
[{"type":"ECOSYSTEM","events":[{"introduced":"5.2.0"},{"fixed":"5.10.252"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.202"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.165"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.128"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.75"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.14"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.4"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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