Security readout for executives and security teams
Plain-English summary
A Linux kernel timing flaw can occur when network-device removal overlaps with an ethtool Netlink operation. The kernel may use synchronization state after device dismantling has begun. The supplied CVSS rates potential confidentiality, integrity, and availability impacts as high. This is a local, authenticated attack surface; the bundle provides no evidence of active exploitation.
Executive priority
Treat this as a high-priority kernel maintenance issue, not an unauthenticated internet emergency. Accelerate remediation on shared Linux systems and environments where local users can administer network devices or device removal occurs frequently. Confirm appliance exposure with vendors because upstream version data alone may not reflect backported fixes.
Technical view
CVE-2025-21701 is a CWE-362 race in ethnl operations. Device unregistration can destroy resources, including the RSS lock, before an operation such as set_channels uses them. The fix widens the ethnl_ops_begin check to reject operations on unregistering devices. The ioctl ethtool path is reportedly unaffected because it obtains the device reference while holding the RTNL lock.
Likely exposure
Exposure is limited to Linux kernels containing the vulnerable ethnl path. The bundle lists 5.16, 5.15.179, 6.1.129, 6.6.76, 6.12.13, 6.13.2, and 6.14 as affected. Its version records mix releases and commit identifiers, so determine exposure using distribution or product-vendor advisories rather than inferred upstream ranges.
Exploitation context
The CVSS vector is local, low complexity, low privilege, and requires no user interaction. Triggering depends on overlapping network-device unregistration with an ethnl operation. The record is not in KEV, and the supplied sources do not report exploitation in the wild, a public exploit, remote reachability, or demonstrated code execution.
Researcher notes
The reported trace involves ethnl_set_channels and a mutex validation warning after device teardown. The vulnerable ordering exists before the RTNL-protected portion of ethnl operations. The supplied material establishes the race and correction but does not establish reliable exploitation, precise outcomes beyond the CVSS assessment, or complete distribution-specific affected ranges.
Mitigation direction
- Apply distribution or product-vendor kernel updates containing the referenced stable fix.
- Ensure the corrected kernel becomes active during the approved maintenance window.
- If patching is delayed, restrict local access and network-device administration according to vendor guidance.
- Review the Debian and Siemens advisories where those products are deployed.
Validation and detection
- Inventory active kernel releases across Linux hosts and appliances.
- Map each release to its distribution or product-vendor CVE status.
- Confirm package changelogs reference CVE-2025-21701 or a cited stable fix.
- Verify the updated kernel is active after maintenance.
- Review kernel logs for related mutex warnings, noting their absence does not prove safety.
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-362: 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-2025-21701 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
- 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
2 official scoresWe 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:H1.85.9LinuxCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H1.45.9CISA-ADPVulnerability 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
Base CVSS 3.1 score
7.4HighVector: CVSS:3.1/AV:L/AC:H/PR:N/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/26bc6076798aa4dc83a07d0a386f9e57c94e8517CVE reference, Linux
- https://git.kernel.org/stable/c/b1cb37a31a482df3dd35a6ac166282dac47664f4CVE reference, Linux
- https://git.kernel.org/stable/c/2f29127e94ae9fdc7497331003d6860e9551cdf3CVE reference, Linux
- https://git.kernel.org/stable/c/b382ab9b885cbb665e0e70a727f101c981b4edf3CVE reference, Linux
- https://git.kernel.org/stable/c/4dc880245f9b529fa8f476b5553c799d2848b47bCVE reference, Linux
- https://git.kernel.org/stable/c/12e070eb6964b341b41677fd260af5a305316a1fCVE reference, Linux
- https://lists.debian.org/debian-lts-announce/2025/03/msg00028.htmlCVE reference, CVE
- https://cert-portal.siemens.com/productcert/html/ssa-082556.htmlCVE reference, siemens-SADP
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.
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.