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CVE-2026-93140

Vulnerability in Linux kernel (CVE-2026-93140)

Summary

Vulnerability in Linux kernel (CVE-2026-93140). Risk of unauthorized operations or information disclosure. Exploitable via BH_Uptodate.

Original description

The description as published by the source.

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

udf: Mark LVID buffer as uptodate before marking it dirty

When an I/O error occurs while writing the Logical Volume Integrity
Descriptor (LVID) buffer to the block device, the block layer's completion
handler (end_buffer_write_sync()) clears the BH_Uptodate flag on the
buffer. However, the buffer still contains valid LVID data in memory. If
the filesystem is subsequently remounted read-write or synced,
udf_open_lvid() or udf_sync_fs() will modify the LVID buffer and call
mark_buffer_dirty(). This triggers a spurious
WARN_ON_ONCE(!buffer_uptodate(bh)) warning in mark_buffer_dirty()
because the buffer is not marked uptodate, even though its in-memory
contents are valid and are about to be overwritten.

To prevent this spurious warning, unconditionally set the BH_Uptodate
flag before calling mark_buffer_dirty() in udf_open_lvid() and
udf_sync_fs(). This acknowledges that the in-memory buffer is valid and
matches the workaround previously applied to udf_close_lvid() in commit
853a0c25baf9 ("udf: Mark LVID buffer as uptodate before marking it dirty").
Extending this workaround ensures consistent behavior across all LVID
updates.

Buffer I/O error on dev loop0, logical block 128, lost sync page write
------------[ cut here ]------------
!buffer_uptodate(bh)
WARNING: fs/buffer.c:1087 at mark_buffer_dirty+0x299/0x410 fs/buffer.c:1087
...
Call Trace:

udf_open_lvid+0x369/0x5b0 fs/udf/super.…

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-2026-93140 has been found in Linux kernel.
Attackers can target a specific entry point like BH_Uptodate over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-93140" on the vendor's site.

CVE-2026-93140 (Linux kernel)
Attack surface: BH_Uptodate
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. Attackers reach the vulnerable code path via BH_Uptodate.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel. Attack surface: BH_Uptodate.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 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":"3.3.0"},{"fixed":"5.10.270"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.221"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.188"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.157"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.110"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.52"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.6"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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