Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2025-39819 medium CVSS 5.5

Vulnerability in Linux kernel (CVE-2025-39819)

Summary

Vulnerability in Linux kernel (CVE-2025-39819). Risk of unauthorized operations or information disclosure. Exploitable via smb2_compound_op.

Original description

The description as published by the source.

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

fs/smb: Fix inconsistent refcnt update

A possible inconsistent update of refcount was identified in smb2_compound_op.
Such inconsistent update could lead to possible resource leaks.

Why it is a possible bug:

  1. In the comment section of the function, it clearly states that the
    reference to cfile should be dropped after calling this function.
  2. Every control flow path would check and drop the reference to
    cfile, except the patched one.
  3. Existing callers would not handle refcount update of cfile if
    -ENOMEM is returned.

To fix the bug, an extra goto label "out" is added, to make sure that the
cleanup logic would always be respected. As the problem is caused by the
allocation failure of vars, the cleanup logic between label "finished"
and "out" can be safely ignored. According to the definition of function
is_replayable_error, the error code of "-ENOMEM" is not recoverable.
Therefore, the replay logic also gets ignored.

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-2025-39819 has been found in Linux kernel.
Attackers can target a specific entry point like smb2_compound_op over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2025-39819" on the vendor's site.

CVE-2025-39819 (Linux kernel) — CVSS v3 5.5
Attack vector: local / no user interaction
Attack surface: smb2_compound_op / cfile / vars / is_replayable_error
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 smb2_compound_op.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel. Attack surface: smb2_compound_op / cfile / vars / is_replayable_error.

🔥 Severity

Severity: Medium (CVSS 5.5/10). 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。

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

We use cookies for analytics and ad measurement. This setting applies to all Game co., Ltd. sites. Details