Security readout for executives and security teams
Plain-English summary
CVE-2025-21774 is a Linux kernel availability bug in the Rockchip CAN FD driver. If a socket buffer allocation fails during receive FIFO overflow handling, the driver can dereference NULL and crash the kernel. The business impact is service disruption on affected Rockchip Linux systems using this CAN controller path.
Executive priority
Handle in normal patch cadence, accelerated for production Rockchip devices where CAN bus availability is operationally important. This is not currently supported as internet-routable or actively exploited from the supplied evidence.
Technical view
The flaw is CWE-476 in rkcanfd_handle_rx_fifo_overflow_int(). The fix changes the handler to bail out when skb allocation fails. CVSS 3.1 is 5.5: local attack vector, low complexity, low privileges, no user interaction, and high availability impact only.
Likely exposure
Exposure appears limited to Linux kernels with the Rockchip rkcanfd CAN FD driver and affected kernel versions or downstream vendor builds. Systems without Rockchip CAN FD hardware, driver support, or the vulnerable kernel code path are less likely to be exposed.
Exploitation context
The source bundle does not show active exploitation, and KEV is false. The CVSS vector indicates exploitation requires local low-privileged access and affects availability, not confidentiality or integrity. No public exploit details are provided in the supplied sources.
Researcher notes
The evidence supports a NULL pointer dereference availability issue only. Affected-version data in the bundle is sparse and may not map cleanly to every downstream kernel. Validate using exact kernel source, vendor patch level, and driver enablement rather than version labels alone.
Mitigation direction
- Update to a kernel containing the referenced stable fixes.
- Check downstream vendor kernel advisories for backported fixes.
- Prioritize Rockchip systems using CAN FD functionality.
- Reduce unnecessary local user access on affected systems.
- Avoid treating non-Rockchip Linux hosts as automatically affected.
Validation and detection
- Inventory Linux kernel versions on Rockchip deployments.
- Confirm whether the rkcanfd driver is built, loaded, or enabled.
- Verify the stable fix commit is present in source or vendor packages.
- Review kernel logs for CAN driver NULL dereference crashes.
- Test CAN functionality after applying vendor or stable kernel updates.
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-2025-21774 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/118fb35681bd2c0d2afa22f7be0ef94bb4d06849CVE reference, Linux
- https://git.kernel.org/stable/c/946750e7865df2e70045071051abf768785dd570CVE reference, Linux
- https://git.kernel.org/stable/c/f7f0adfe64de08803990dc4cbecd2849c04e314aCVE 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.
NULL Pointer Dereference
NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.