Security readout for executives and security teams
Plain-English summary
A Linux Btrfs race can occur when two threads share one file descriptor: one performs direct writes while the other synchronizes data. The race may crash the kernel or cause invalid kernel-memory access. It requires local access and a specific concurrent I/O pattern; it is not described as remotely exploitable.
Executive priority
Treat this as a high-priority kernel maintenance issue for Btrfs systems that run untrusted or multi-tenant local workloads. It is less urgent for systems without Btrfs or without relevant local workload access. Use normal emergency-kernel testing and reboot procedures; the supplied evidence does not justify describing it as an active internet-scale threat.
Technical view
The race involves temporary, stack-backed file-private state used by btrfs_direct_write(). A concurrent btrfs_sync_file() may incorrectly skip the inode lock or access that state after its lifetime ends. Reported outcomes include a failed locking assertion, kernel BUG, and invalid memory access. CVSS 3.1 is 7.8: local, low complexity, low privileges, no user interaction.
Likely exposure
Exposure requires Linux systems using Btrfs and local code capable of concurrent O_DIRECT writes and fsync or fdatasync operations through the same file descriptor. The bundle explicitly marks Linux 5.15.165, 6.1.105, 6.6.46, and 6.10.5 as unaffected. Other versions require distribution or vendor confirmation.
Exploitation context
The supplied sources provide no evidence of active exploitation, and the CVE is not listed as KEV in the bundle. Triggering requires a local, low-privileged context and a particular multithreaded I/O pattern. The documented evidence demonstrates kernel failure and unsafe memory access, but does not establish practical privilege escalation or data compromise.
Researcher notes
The core defect is a lifetime and synchronization race around file-private state shared through a common descriptor. The CVSS claims high confidentiality, integrity, and availability impact, while the narrative directly documents assertion failure and invalid memory access. Because the affected-version metadata is unusual and incomplete, map fixes through vendor backports and commit history rather than version assumptions.
Mitigation direction
- Install a vendor-supported kernel containing the applicable upstream stable fix.
- Confirm remediation against the distribution advisory; do not rely solely on upstream version numbering.
- Until updated, avoid sharing one O_DIRECT file descriptor between concurrent writes and fsync operations.
- Prioritize Btrfs hosts running untrusted local workloads or storage-intensive multi-tenant services.
Validation and detection
- Inventory kernel versions and identify systems with mounted Btrfs filesystems.
- Compare each kernel package against its distribution advisory and fixed build.
- Check vendor changelogs for the corresponding upstream stable correction.
- Review kernel logs for Btrfs assertion failures, BUG messages, oopses, or invalid memory accesses.
- Verify the updated kernel is active after reboot, not merely installed.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CVE-2024-46734 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9LinuxVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/d116a0b0e02f395cedfb8c725bd67480aa7c428cCVE reference, Linux
- https://git.kernel.org/stable/c/cd3087582e4fa36e89be4e6f859e75a4400292b4CVE reference, Linux
- https://git.kernel.org/stable/c/7b5595f33c3c273613b590892a578d78186bb400CVE reference, Linux
- https://git.kernel.org/stable/c/01681aa609b5f110502f56c4e3b2938efcf4a5bcCVE reference, Linux
- https://git.kernel.org/stable/c/cd9253c23aedd61eb5ff11f37a36247cd46faf86CVE reference, Linux
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.htmlCVE reference, CVE
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.