CVE-2026-21308VulnerabilityPublished 13 Jan 2026Updated 27 Aug 2026

CVE-2026-21308: 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 25 Oct 2026, 19:02 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 8% 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 13 Jan 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 2026-10-25.

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 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 <=15.0.3	Fixed in–

AI-suggested

To mitigate CVE-2026-21308, European organizations should: 1) Immediately update Adobe Substance3D - Designer to the latest version once Adobe releases a patch addressing this vulnerability. 2) Until a patch is available, implement strict file handling policies that restrict opening files from untrusted or unknown sources, especially email attachments or downloads. 3) Educate users about the risks of opening unsolicited or suspicious files and train them to recognize phishing attempts that may deliver malicious content. 4) Employ endpoint security solutions capable of detecting and blocking malicious files or anomalous application behavior related to Adobe Substance3D. 5) Use network segmentation to limit exposure of critical design workstations and monitor for unusual file access or data exfiltration attempts. 6) Regularly audit and monitor logs for signs of exploitation attempts or memory disclosure activities. 7) Coordinate with Adobe support channels to receive timely updates and advisories regarding this vulnerability.

Description

Substance3D - Designer versions 15.0.3 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, the primary impact of CVE-2026-21308 is the potential leakage of sensitive information from memory when users open malicious files in Adobe Substance3D - Designer. This could include intellectual property, design assets, or other confidential data processed by the software. While the vulnerability does not enable system takeover or data modification, the confidentiality breach could have significant consequences for companies in sectors such as media, entertainment, manufacturing, and product design. Exposure of proprietary design data could lead to competitive disadvantages or intellectual property theft. Additionally, the requirement for user interaction means phishing or social engineering could be used to deliver malicious files, increasing risk in environments with less stringent user training or file handling policies. The absence of known exploits reduces immediate threat but does not eliminate the risk of future targeted attacks. Organizations with remote or hybrid work models may face increased exposure if users handle files from untrusted sources.

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/apsb26-13.html (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 21 Jan 2026, 02:52 UTC

WeaknessesCWE-125

Technical details

References

Community reviews

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