CVE-2026-103840
HIGH 7.8Substance3D - Stager is affected by an out-of-bounds read vulnerability when parsing a crafted file, which could result in a read past the end of an allocated memory structure. An attacker could leverage this vulnerability to execute code in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.
Severe if exploited (CVSS 7.8), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.2%chance of exploitation in 30 days · 6th percentile
Impact if exploited
7.8CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ⚠Access: Requires local access to the host
- ✓Privileges: No account or privileges required
- ⚠User interaction: A user must take an action (click / open a file)
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-103840/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-103840/poc.json
Weakness (CWE)
- CWE-125: Out-of-bounds Read (CWE-125)
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
All CVSS metrics
- HIGH 7.8 v3.1 · CNA Primary
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - HIGH 7.8 v3.1 · NVD Secondary
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H