Security readout for executives and security teams
Plain-English summary
A flaw in the Linux mlx5 RDMA driver can schedule the same memory object for destruction twice. The second cleanup may access memory already freed by the first, potentially compromising confidentiality, integrity, or availability. Exploitation requires local low-privilege access and relevant RDMA functionality, so exposure is concentrated in RDMA-enabled servers rather than general internet-facing Linux systems.
Executive priority
Treat as a high-priority infrastructure patch for shared RDMA, HPC, virtualization, and multi-tenant systems using mlx5. Standard Linux servers without relevant RDMA use have lower practical urgency. First establish feature reachability, then patch exposed hosts through normal kernel maintenance. Emergency internet-wide action is not supported by the supplied evidence.
Technical view
The mlx5 implicit on-demand paging path can double-queue destruction of a memory region. A later worker may invalidate the already-freed region, producing a CWE-416 use-after-free and refcount underflow. The linked stable fixes use __xa_cmpxchg() to ensure only one destruction attempt proceeds. CVSS 3.1 is 7.8: local, low complexity, low privileges, no user interaction.
Likely exposure
Likely exposure is limited to affected Linux kernels using the mlx5_ib RDMA driver with implicit ODP. Systems permitting untrusted users, containers, or tenants to access RDMA deserve priority. The supplied affected-version data includes 5.5, 6.12.13, 6.13.2, and 6.14, but its exact range semantics are incomplete; verify distribution-specific status.
Exploitation context
The CVSS vector describes a local, low-privilege attack with no user interaction. The source bundle contains a reproduced kernel warning and use-after-free trace, but no evidence of public weaponization or active exploitation. The CVE is not listed as KEV in the supplied data. Internet exposure alone does not establish reachability.
Researcher notes
The failure involves duplicate invalidation and destruction work for an implicit ODP memory region. The second worker can run after the first frees the object. The fix provides atomic ownership of destruction through __xa_cmpxchg(). The bundle does not establish reliable release-range boundaries, exploitability beyond the reported trace, or active exploitation; downstream advisories are needed for build-level conclusions.
Mitigation direction
- Update to a vendor-supported kernel containing the applicable linked stable fix or backport.
- Prioritize RDMA hosts accessible by untrusted local users, workloads, containers, or tenants.
- If patching is delayed, restrict untrusted access to mlx5 RDMA functionality pending vendor guidance.
- Consult the Linux distributor's advisory for precise affected and fixed package versions.
Validation and detection
- Inventory running kernels where mlx5_ib, RDMA, and implicit ODP are used.
- Map each kernel build against the CVE record and distributor-specific advisories.
- Verify package changelogs or kernel sources include the applicable linked fix or backport.
- Review kernel logs for refcount underflow or free_implicit_child_mr_work warnings.
- After updating, validate RDMA workloads and confirm the running kernel is the remediated build.
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-416: 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-2025-21714 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:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9CISA-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
7.8HighVector: 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/7cc8f681f6d4ae4478ae0f60485fc768f2b450daCVE reference, Linux
- https://git.kernel.org/stable/c/edfb65dbb9ffd3102f3ff4dd21316158e56f1976CVE reference, Linux
- https://git.kernel.org/stable/c/d3d930411ce390e532470194296658a960887773CVE reference, Linux
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.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.