Security readout for executives and security teams
Plain-English summary
This is a Linux kernel availability flaw on RISC-V systems. A local user able to use kernel kprobe tracing can trigger a kernel panic when sys_read is probed. The business impact is service disruption, not data theft or privilege escalation based on the supplied sources.
Executive priority
Prioritize patching where RISC-V Linux hosts support production workloads or shared local access. The urgency is moderate because impact is high availability loss, but exploitation requires local access and the sources do not show active exploitation.
Technical view
The issue is in RISC-V kprobe handling. Placing a kprobe at sys_read can replace the first instruction with ebreak; a page-fault path during single-step leaves interrupt state mishandled, leading to a BUG_ON in fs/buffer.c and kernel panic.
Likely exposure
Exposure appears limited to affected Linux kernel versions on RISC-V platforms where kprobe/ftrace debug tracing is available to a local user or operator. General x86 or ARM Linux systems are not shown as affected in the provided bundle.
Exploitation context
The bundle provides a local reproducer pattern and CVSS AV:L/PR:L/UI:N/A:H. CISA KEV is false, and no cited source states active exploitation. Treat this as a local denial-of-service risk for RISC-V Linux hosts.
Researcher notes
The evidence points to a RISC-V-specific kprobe state-handling bug triggered during sys_read tracing. The supplied CVE text is partially truncated, so exact version boundaries should be verified against the stable commits and downstream vendor backports.
Mitigation direction
- Update to a vendor kernel containing the referenced Linux stable fixes.
- Check vendor advisories if exact fixed package versions are unclear.
- Restrict access to kprobe, ftrace, and debugfs tracing interfaces.
- Avoid using kprobes on sys_read on affected RISC-V kernels until patched.
Validation and detection
- Inventory RISC-V Linux systems and record kernel versions.
- Confirm whether vendor packages include the referenced stable commits.
- Review access controls for debugfs, ftrace, and kprobe tracing interfaces.
- Check monitoring for unexplained kernel panics on RISC-V hosts.
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
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CVE-2021-46957 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/fd0f06590d35c99f98d12c7984897ec4201a6263CVE reference, Linux
- https://git.kernel.org/stable/c/b1ebaa0e1318494a7637099a26add50509e37964CVE 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.