VulnerabilityPublished 10 Feb 2026Updated 27 Aug 2026

CVE-2026-21339: Adobe Substance 3D Designer · Out-of-bounds Read

Affects Adobe Substance 3D DesignerSource CVE Database V5

Not known to be exploited · CVSS 5.5 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

5.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Attack Vector: Local
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
AdobeAdobe Substance 3D Designer	Affected <=15.1.1	Fixed in–

AI-suggested

Monitor Adobe’s official channels for patches addressing CVE-2026-21339 and apply updates promptly once available.
Implement strict file handling policies to restrict opening files from untrusted or unknown sources, reducing the risk of malicious file execution.
Educate users on the risks of opening unsolicited or suspicious files, emphasizing the importance of verifying file origins.
Employ endpoint security solutions capable of detecting anomalous behavior related to file processing in Adobe Substance3D - Designer.
Utilize memory protection mechanisms such as Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR) to mitigate exploitation impact.
Conduct regular security audits and penetration testing focused on creative software environments to identify and remediate similar vulnerabilities.
Consider network segmentation for systems running Substance3D to limit potential lateral movement if exploitation occurs.
Maintain robust incident response plans tailored to data leakage scenarios involving design and creative assets.

Description

Substance3D - Designer versions 15.1.0 and earlier are affected by an out-of-bounds read vulnerability that could lead to memory exposure. An attacker could leverage this vulnerability to disclose sensitive information stored in memory. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

Impact

For European organizations, especially those in creative industries such as digital media, gaming, advertising, and product design, this vulnerability poses a risk of sensitive data leakage. The exposed memory could contain proprietary design data, user credentials, or other confidential information, potentially leading to intellectual property theft or privacy violations. Since exploitation requires user interaction, the risk is mitigated somewhat by user awareness and secure handling of files. However, targeted spear-phishing campaigns could leverage this vulnerability to compromise high-value design assets. The medium severity indicates that while the vulnerability is not critical, it still represents a meaningful threat to confidentiality. Organizations relying heavily on Adobe Substance3D - Designer for their workflows may face reputational damage and operational risks if sensitive data is disclosed. The absence of known exploits reduces immediate risk but does not eliminate the need for proactive mitigation.

CWE-125Out-of-bounds Read (opens in a new tab)
Base weaknessCWE Top 25 (2025): #8
The product reads data past the end, or before the beginning, of the intended buffer.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design · Language Selection
Use a language that provides appropriate memory abstractions.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Overread Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

helpx.adobe.com/security/products/substance3d_designer/apsb26-19.html (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Feb 2026, 18:47 UTC

WeaknessesCWE-125

Technical details

References

Community reviews

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