Bug 2395200 (CVE-2025-39800)

Summary: CVE-2025-39800 kernel: Linux kernel (btrfs): Denial of Service due to unexpected metadata generation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's btrfs filesystem. A local user could exploit this vulnerability when the system processes an unexpected generation for an extent buffer during a root copy operation. Instead of properly stopping the transaction, the system allows corrupted metadata to persist. This issue can lead to a denial of service (DoS), making the system or data unavailable.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-09-15 13:01:40 UTC 
In the Linux kernel, the following vulnerability has been resolved:

btrfs: abort transaction on unexpected eb generation at btrfs_copy_root()

If we find an unexpected generation for the extent buffer we are cloning
at btrfs_copy_root(), we just WARN_ON() and don't error out and abort the
transaction, meaning we allow to persist metadata with an unexpected
generation. Instead of warning only, abort the transaction and return
-EUCLEAN.
Comment 1 Keith Grant 2025-09-15 16:38:13 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025091549-CVE-2025-39800-6b30@gregkh/T