Security readout for executives and security teams
Plain-English summary
Adobe Substance 3D Stager 3.1.6 and earlier can be compromised when a user opens a maliciously crafted file. Successful exploitation could let an attacker run code with the user’s permissions, potentially exposing data, changing files, or disrupting the workstation.
Executive priority
Prioritize remediation for affected creative workstations, especially those exchanging files externally. This is high priority because compromise can affect confidentiality, integrity, and availability, although exploitation requires a user to open a malicious file.
Technical view
CVE-2026-21343 is a CWE-125 out-of-bounds read in crafted-file parsing. Reading beyond an allocated memory structure can lead to code execution as the current user. It has CVSS 3.1 score 7.8, requires local file access and user interaction, and requires no prior privileges.
Likely exposure
Exposure is most likely on workstations running Substance 3D Stager 3.1.6 or earlier, particularly where users receive project files from external or untrusted sources. The supplied structured version data is ambiguous, so inventories should be checked against Adobe’s advisory.
Exploitation context
A victim must open a malicious file in the affected application. The provided sources do not establish active exploitation, and the CVE is not identified as being in CISA’s Known Exploited Vulnerabilities catalog.
Researcher notes
The source description identifies versions 3.1.6 and earlier, while the structured affected entry contains boundary values “0” and “3.1.7” with default status unaffected. Confirm the exact range with Adobe before closing findings. No exploit method beyond crafted-file parsing is established by the supplied evidence.
Mitigation direction
- Inventory Substance 3D Stager installations and identify versions 3.1.6 or earlier.
- Follow Adobe’s advisory to install a release explicitly identified as not affected.
- Restrict or scrutinize Stager files received from untrusted or unexpected sources.
- Use endpoint controls to limit the impact of code running with user permissions.
Validation and detection
- Confirm installed Stager versions through software inventory or endpoint-management records.
- Verify the deployed release against the affected-version guidance in Adobe’s advisory.
- Review security telemetry around Stager file-opening events for anomalous behavior.
- Confirm users cannot bypass required application updates on managed 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-125: 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-2026-21343 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:N/UI:R/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
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:N/UI:R/S:U/C:H/I:H/A:H1.85.9adobeVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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://helpx.adobe.com/security/products/substance3d_stager/apsb26-20.htmlCVE reference, adobe · vendor-advisory
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.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.