Security readout for executives and security teams
Plain-English summary
A malicious project file can corrupt memory in Adobe Substance 3D Stager and run attacker-controlled code with the victim’s permissions. An attacker must persuade a user to open the file. Successful exploitation could expose data, alter files, or disrupt the application and user account.
Executive priority
Prioritize prompt remediation on creative workstations that exchange external files. The impact can be severe, but exploitation requires a user to open a malicious file. Pair updating with short-term file-handling controls and user awareness.
Technical view
CVE-2026-21341 is an out-of-bounds write (CWE-787) in Substance 3D Stager 3.1.6 and earlier. It may enable arbitrary code execution as the current user. CVSS 3.1 rates it 7.8: local attack vector, low complexity, no privileges required, user interaction required, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is concentrated on endpoints running Substance 3D Stager 3.1.6 or earlier, especially where users receive project files from external or untrusted sources. User interaction limits drive-by risk, but creative teams, contractors, and shared production workflows may be credible targets.
Exploitation context
The supplied sources require a victim to open a malicious file. The CVE is not listed as KEV in the bundle, and no cited evidence establishes active exploitation. Absence from KEV does not prove exploitation is impossible or nonexistent.
Researcher notes
The bundle’s narrative says 3.1.6 and earlier are affected, while its structured affected entry contains boundaries “0” and “3.1.7” without explicit range semantics. Confirm the precise fixed-version boundary in Adobe APSB26-20. No exploit method or active campaign is established by the supplied evidence.
Mitigation direction
- Inventory Substance 3D Stager installations and identify versions 3.1.6 or earlier.
- Review Adobe advisory APSB26-20 and apply its vendor-designated update or remediation.
- Until remediated, prevent users from opening untrusted Stager files.
- Use endpoint controls to limit damage from code executing under user accounts.
Validation and detection
- Confirm installed Stager versions through software inventory and direct endpoint checks.
- Verify affected installations received the Adobe-designated fixed release.
- Review endpoint telemetry for suspicious activity following Stager file access.
- Test that controls block or warn on untrusted project files.
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-787: 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-21341 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 Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.