Improper input validation in upx
Priority LOW 27CWE-20Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-617.
Summary
An assertion abort was found in upx MemBuffer::alloc() in mem.cpp, in version UPX 4.0.0. The flow allows attackers to cause a denial of service (abort) via a crafted file.
Why it matters now
EPSS 0.01041 64th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | upx | upx 4.0 | — | No fix listed | CNA |
- upx Vendor— Affected upx 4.0 Fixed in — No fix listed CNA
CPE configurations NVD · 3
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:upx:upx:4.0.0:*:*:*:*:*:*:* | 4.0.0 | Vulnerable | Upx |
| cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Red Hat |
| cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* | 33 | Vulnerable | Fedoraproject |
- cpe:2.3:a:upx:upx:4.0.0:*:*:*:*:*:*:* Versions 4.0.0 Vulnerable ·Upx
- cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Red Hat
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2021-30501
- 2026-10-03 Alias added: GHSA-88gh-wqj4-3fxr
References
Sources
- CVE-2021-30501 · CVE Program
- CVE-2021-30501 · NVD
- FIRST EPSS
- GHSA-88gh-wqj4-3fxr · GitHub Advisory Database · CC BY 4.0
- CVE-2021-30501 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences