Security readout for executives and security teams
Plain-English summary
UPX can crash when asked to inspect a specially crafted 64-bit Linux ELF file. The documented impact is denial of service, not data theft or remote code execution. Business risk is highest where automated build, malware-analysis, or file-processing workflows run UPX on untrusted files.
Executive priority
Treat as a targeted operational stability issue. Prioritize remediation for automated pipelines that process external files, because a crash could interrupt analysis or build workflows. It is not currently evidenced as a broad compromise risk.
Technical view
CVE-2020-27788 is a CWE-125 out-of-bounds read in UPX PackLinuxElf64::canPack() in p_lx_elf.cpp. A crafted input file can trigger a crash. The source bundle states the issue is fixed in UPX v3.96, but does not provide CVSS scoring or a complete vulnerable version range.
Likely exposure
Exposure is likely limited to systems that use UPX and process attacker-controlled or untrusted Linux ELF inputs. General endpoints are less exposed unless UPX is part of automated unpacking, scanning, build, reverse-engineering, or ingestion pipelines.
Exploitation context
The provided sources do not show active exploitation, and KEV status is false. The known attack condition is supplying a crafted input file to UPX. Evidence supports denial of service through a crash only.
Researcher notes
The public record is sparse: no CVSS, no listed active exploitation, and no complete affected version range in the bundle. Research should focus on UPX version discovery, untrusted input paths, and whether fixed code from commit 1bb93d4f is present.
Mitigation direction
- Upgrade UPX to v3.96 or a later vendor-recommended release.
- Avoid processing untrusted files with vulnerable UPX versions.
- Run UPX file processing in isolated, resource-limited environments.
- Check vendor guidance for any additional hardening or backported fixes.
Validation and detection
- Inventory systems and pipelines that invoke UPX.
- Confirm installed UPX versions are v3.96 or later.
- Identify workflows where UPX receives external or untrusted files.
- Review crash logs for UPX failures during ELF processing.
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-125: 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 lookupCVE-2020-27788 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/upx/upx/issues/332CVE reference · x_refsource_MISC
- https://github.com/upx/upx/commit/1bb93d4fce9f1d764ba57bf5ac154af515b3fc83CVE reference · x_refsource_MISC
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 Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.