Security readout for executives and security teams
Plain-English summary
CVE-2025-21937 is a Linux kernel Bluetooth flaw that can crash affected systems through a null pointer dereference. The business impact is availability, not data theft. The source bundle rates it medium with CVSS 5.5, requiring local access and low privileges. No provided source shows active exploitation.
Executive priority
Address through normal kernel patch management, with higher priority for multi-user endpoints or systems where local denial of service affects operations. This is not presented as a remote compromise or data exposure issue in the provided sources.
Technical view
The issue is CWE-476 in the Linux Bluetooth management path. mgmt_remote_name() did not check whether mgmt_alloc_skb() returned null, allowing a kernel null pointer dereference. The CVSS vector is local, low complexity, low privileges, no user interaction, with high availability impact only.
Likely exposure
Exposure is most relevant for Linux systems running source-listed affected kernel versions with Bluetooth management functionality available. Servers without Bluetooth hardware or disabled Bluetooth services are likely less exposed, but kernel package status should still be checked against vendor advisories.
Exploitation context
The CVSS vector indicates local exploitation with low privileges and no user interaction. The provided data does not include exploit availability, in-the-wild use, or KEV listing. Treat this as a denial-of-service risk unless vendor guidance adds more detail.
Researcher notes
Evidence supports a kernel availability bug fixed by adding an allocation-failure check. Affected-version detail in the bundle is limited to CVE records and stable commit references; use distribution advisories for precise package mapping. Do not infer remote reachability from Bluetooth involvement alone.
Mitigation direction
- Update to a kernel containing the referenced stable fixes.
- Apply Debian LTS or distribution kernel updates where applicable.
- Disable or restrict Bluetooth where it is unnecessary.
- Check vendor advisories for exact fixed package versions.
- Prioritize shared, desktop, kiosk, and exposed Linux endpoints.
Validation and detection
- Inventory Linux kernel versions across managed systems.
- Confirm Bluetooth support or services are present where risk matters.
- Map installed kernels to distribution security advisories.
- Verify patched kernels include the referenced stable commits.
- Review crash logs for Bluetooth-related null dereference events.
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
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-476: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2025-21937 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:N/I:N/A:H1.83.6CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
5.5MediumVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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/37785a01040cb5d11ed0ddbcbf78491fcd073161CVE reference, Linux
- https://git.kernel.org/stable/c/c5845c73cbacf5704169283ef29ca02031a36564CVE reference, Linux
- https://git.kernel.org/stable/c/88310caff68ae69d0574859f7926a59c1da2d60bCVE reference, Linux
- https://git.kernel.org/stable/c/69fb168b88e4d62cb31cdd725b67ccc5216cfcafCVE reference, Linux
- https://git.kernel.org/stable/c/f2176a07e7b19f73e05c805cf3d130a2999154cbCVE reference, Linux
- https://lists.debian.org/debian-lts-announce/2025/05/msg00045.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.
NULL Pointer Dereference
NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.