Security readout for executives and security teams
Plain-English summary
A malicious project file opened in Adobe Substance 3D Painter could corrupt memory and run attacker-controlled code with the victim’s account permissions. The supplied description identifies versions 11.0.3 and earlier. Because exploitation requires opening a malicious file, organizations handling untrusted creative assets face the greatest risk.
Executive priority
Prioritize remediation for creative teams receiving external files. Treat this as high priority, but not an emergency equivalent to confirmed active exploitation. Confirm Adobe’s corrected version boundary before declaring systems safe because the supplied records contain inconsistent version information.
Technical view
CVE-2026-21305 is a CWE-787 out-of-bounds write with CVSS 3.1 score 7.8. It is locally triggered, requires no privileges, and requires user interaction. Successful exploitation could compromise confidentiality, integrity, and availability in the current user’s context.
Likely exposure
Likely exposure includes workstations running Substance 3D Painter 11.0.3 or earlier whose users open externally supplied or otherwise untrusted files. The bundle’s separate affected-version data references 11.1.2, conflicting with the description, so inventories between these versions require vendor confirmation.
Exploitation context
The victim must open a malicious file. The source bundle does not place this CVE in CISA KEV and provides no evidence of active exploitation. An attacker would likely depend on file delivery and user action rather than unauthenticated remote access.
Researcher notes
The CVSS vector is AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Arbitrary code executes as the current user. The description says 11.0.3 and earlier, while structured affected data references 0 through 11.1.2 with default status unaffected; the precise boundary cannot be resolved from this bundle alone.
Mitigation direction
- Review Adobe’s advisory for the supported fixed release and install vendor-approved updates.
- Prioritize systems that regularly process files from customers, vendors, downloads, or shared repositories.
- Restrict opening untrusted Substance 3D Painter files until affected systems are remediated.
- Use least-privilege user accounts to reduce the consequences of successful code execution.
Validation and detection
- Inventory installed Substance 3D Painter versions across managed endpoints.
- Flag version 11.0.3 and earlier, then resolve the 11.1.2 discrepancy using Adobe’s advisory.
- Confirm remediated endpoints run the vendor-designated fixed version.
- Review endpoint alerts involving Painter and recently opened files from untrusted sources.
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-2026-21305 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_painter/apsb26-10.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.