Linux Kernel up to 6.17-rc3 smb2_compound_op control flow

CVSS Meta Temp Score
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CTI Interest Score
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5.4$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.149/6.6.103/6.12.44/6.16.4/6.17-rc3 and classified as critical. This vulnerability affects the function smb2_compound_op. The manipulation results in control flow. This vulnerability is identified as CVE-2025-39819. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.1.149/6.6.103/6.12.44/6.16.4/6.17-rc3. Affected is the function smb2_compound_op. The manipulation with an unknown input leads to a control flow vulnerability. CWE is classifying the issue as CWE-670. The code contains a control flow path that does not reflect the algorithm that the path is intended to implement, leading to incorrect behavior any time this path is navigated. The impact remains unknown. CVE summarizes:

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.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2025-39819 since 04/16/2025. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 01/16/2026).

The vulnerability scanner Nessus provides a plugin with the ID 265199 (Linux Distros Unpatched Vulnerability : CVE-2025-39819), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.150, 6.6.104, 6.12.45, 6.16.5 or 6.17-rc4 eliminates this vulnerability. Applying the patch 3fc11ff13fbc2749871d6ac2141685cf54699997/4191ea1f0bb3e27d65c5dcde7bd00e709ec67141/4735f5991f51468b85affb8366b7067248457a71/cc82c6dff548f0066a51a6e577c7454e7d26a968/ab529e6ca1f67bcf31f3ea80c72bffde2e9e053e is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (265199) and CERT Bund (WID-SEC-2025-2077). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • IBM QRadar SIEM
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux
  • Dell Secure Connect Gateway

Productinfo

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Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.4

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Control flow
CWE: CWE-670
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 265199
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-39819

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.150/6.6.104/6.12.45/6.16.5/6.17-rc4
Patch: 3fc11ff13fbc2749871d6ac2141685cf54699997/4191ea1f0bb3e27d65c5dcde7bd00e709ec67141/4735f5991f51468b85affb8366b7067248457a71/cc82c6dff548f0066a51a6e577c7454e7d26a968/ab529e6ca1f67bcf31f3ea80c72bffde2e9e053e

Timelineinfo

04/16/2025 CVE reserved
09/16/2025 +153 days Advisory disclosed
09/16/2025 +0 days VulDB entry created
01/16/2026 +122 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-39819 (🔒)
GCVE (CVE): GCVE-0-2025-39819
GCVE (VulDB): GCVE-100-324426
CERT Bund: WID-SEC-2025-2077 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 09/16/2025 16:00
Updated: 01/16/2026 22:33
Changes: 09/16/2025 16:00 (58), 09/20/2025 02:05 (2), 10/21/2025 08:55 (7), 12/27/2025 13:43 (1), 01/16/2026 22:33 (10)
Complete: 🔍
Cache ID: 216::103

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