Security readout for executives and security teams
Plain-English summary
This is a Linux kernel memory leak in the sun8i-ss crypto driver. A local authenticated user could trigger a failed DMA mapping path that leaks memory, potentially degrading availability. The sources do not indicate data theft, integrity loss, remote access, or active exploitation.
Executive priority
Treat this as a moderate operational reliability issue. It is not evidenced as remotely exploitable or actively exploited, but affected embedded or ARM Linux systems could suffer availability degradation. Patch through normal kernel maintenance, with higher urgency for systems relying on sun8i crypto hardware.
Technical view
The vulnerable error path occurs when dma_iv mapping fails in the sun8i-ss crypto code. Memory allocated for object d was not freed before returning. The upstream fix adds an error label so the allocation is freed on this failure path. CVSS 3.1 is 5.5, local, low complexity, low privileges, availability impact only.
Likely exposure
Exposure is most relevant to Linux systems running affected kernels with the sun8i-ss crypto driver or supported Allwinner sun8i hardware path present. The bundle identifies Linux kernel versions around 5.10 through 5.13 as affected, but distribution backports may change practical exposure.
Exploitation context
No active exploitation is supported by the provided sources. The CVE is not marked KEV, and the cited material describes a resource leak found through Coverity rather than a public exploit. Abuse would require local low-privilege access and impact availability, not confidentiality or integrity.
Researcher notes
The source evidence is narrow: a kernel memory leak on a dma_iv mapping failure path, classified under CWE-770. The most useful validation is version and driver exposure mapping. Do not assume all Linux systems are affected; practical risk depends on kernel build, hardware, and distro backports.
Mitigation direction
- Update affected Linux kernels using vendor packages that include the referenced stable fixes.
- Prioritize systems with Allwinner sun8i crypto accelerator support or the sun8i-ss driver enabled.
- If immediate updating is unavailable, follow Linux distribution or vendor mitigation guidance.
- Track kernel and distro advisories for backports tied to CVE-2021-47057.
Validation and detection
- Inventory Linux kernel versions and compare them with vendor-fixed builds for this CVE.
- Confirm whether the sun8i-ss crypto driver is present, enabled, or loaded on target systems.
- Check distribution changelogs for the referenced stable kernel commits or CVE backport notes.
- Review monitoring for unexplained memory pressure on affected embedded or ARM Linux systems.
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-770: 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-2021-47057 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/617ec35ed51f731a593ae7274228ef2cfc9cb781CVE reference, Linux
- https://git.kernel.org/stable/c/e1f2d739849c3239df1ea3f97d40bade4b808410CVE reference, Linux
- https://git.kernel.org/stable/c/6516cb852d704ff8d615de1f93cd443a99736c3dCVE reference, Linux
- https://git.kernel.org/stable/c/98b5ef3e97b16eaeeedb936f8bda3594ff84a70eCVE 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.
Allocation of Resources Without Limits or Throttling
Allocation of Resources Without Limits or Throttling represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.