Security readout for executives and security teams
Plain-English summary
This is a Linux kernel memory leak in the Venus video decoder path. A local user with some system access could trigger repeated allocation failures that leave memory unreleased, potentially degrading or denying service. The public bundle does not indicate data theft, privilege escalation, or active exploitation.
Executive priority
Treat as a routine but real availability risk for Linux fleets with the relevant video decoder path. Patch through normal kernel maintenance, with higher priority for shared, multi-user, embedded, or availability-sensitive systems.
Technical view
CVE-2021-47655 is a CWE-401 resource leak in venus_helper_alloc_dpb_bufs(). An early return after ida_alloc_min() failure could skip freeing a previously allocated DMA buffer. The fix moves cleanup to a common failure path. CVSS 3.1 is 5.5, local attack vector, low privileges, no user interaction, high availability impact.
Likely exposure
Exposure appears limited to Linux systems using the media Venus video decoder driver path. Prioritize kernels matching the CVE record's affected Linux entries and systems with relevant video decoding hardware or enabled driver support. Distribution backport status is not provided in the bundle.
Exploitation context
The source bundle marks KEV as false and provides no evidence of active exploitation. The CVSS vector requires local access and low privileges. Impact is availability-focused through memory exhaustion or instability, not confidentiality or integrity compromise.
Researcher notes
Evidence supports a local, low-complexity availability issue caused by missed cleanup on an error path. The bundle does not provide exploit details, affected downstream distributions, or product-specific advisories beyond Linux kernel references. Avoid assuming broad internet exposure.
Mitigation direction
- Apply vendor or distribution kernel updates containing the referenced stable fixes.
- Check Linux kernel advisories for backported fixes in supported distribution kernels.
- Reduce exposure to untrusted local users where affected systems cannot be updated quickly.
- Review whether the Venus video decoder driver is enabled or used on relevant systems.
Validation and detection
- Inventory kernel versions against CVE-2021-47655 and distribution security advisories.
- Confirm whether the media Venus video decoder driver is built, loaded, or reachable.
- Verify patch presence by checking for the referenced stable commits or vendor backports.
- Monitor affected systems for memory pressure or video decoder related kernel errors.
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-401: 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-2021-47655 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/5cedfe8aaf1875a5305897107b7f298db4260019CVE reference, Linux
- https://git.kernel.org/stable/c/55bccafc246b2e64763a155ec454470c07a54a6eCVE reference, Linux
- https://git.kernel.org/stable/c/5f89d05ba93df9c2cdfe493843f93288e55e99ebCVE reference, Linux
- https://git.kernel.org/stable/c/8403fdd775858a7bf04868d43daea0acbe49ddfcCVE 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.
Missing Release of Memory after Effective Lifetime
Missing Release of Memory after Effective Lifetime represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.