CVE-2025-39819
fs/smb: Fix inconsistent refcnt update
Description
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.
INFO
Published Date :
Sept. 16, 2025, 1:15 p.m.
Last Modified :
Jan. 16, 2026, 8:09 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Ensure refcount logic handles all control flow paths.
- Drop reference to cfile in all exit scenarios.
- Apply the provided patch to the Linux kernel.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-39819.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-39819 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-39819
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-39819 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-39819 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jan. 16, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE NVD-CWE-noinfo Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.16.5 *cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.45 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.104 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.8 up to (excluding) 6.1.150 Added CPE Configuration OR *cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* Added Reference Type kernel.org: https://git.kernel.org/stable/c/3fc11ff13fbc2749871d6ac2141685cf54699997 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/4191ea1f0bb3e27d65c5dcde7bd00e709ec67141 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/4735f5991f51468b85affb8366b7067248457a71 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/ab529e6ca1f67bcf31f3ea80c72bffde2e9e053e Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/cc82c6dff548f0066a51a6e577c7454e7d26a968 Types: Patch Added Reference Type CVE: https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html Types: Third Party Advisory -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 03, 2025
Action Type Old Value New Value Added Reference https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 16, 2025
Action Type Old Value New Value Added Description 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. Added Reference https://git.kernel.org/stable/c/3fc11ff13fbc2749871d6ac2141685cf54699997 Added Reference https://git.kernel.org/stable/c/4191ea1f0bb3e27d65c5dcde7bd00e709ec67141 Added Reference https://git.kernel.org/stable/c/4735f5991f51468b85affb8366b7067248457a71 Added Reference https://git.kernel.org/stable/c/ab529e6ca1f67bcf31f3ea80c72bffde2e9e053e Added Reference https://git.kernel.org/stable/c/cc82c6dff548f0066a51a6e577c7454e7d26a968