CVE-2020-27796

Exp

A heap-based buffer over-read was discovered in the invert_pt_dynamic function in p_lx_elf.cpp in UPX 4.0.0 via a crafted Mach-O file.

Published: 2022-08-25 Last update: 2025-04-11 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-27796 is rated Exploit Available (55.9/100): CVSS High severity, with low exploitation likelihood (EPSS 0.10%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2020-27796

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2020-27796

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-10-26 0.05% 0.10% +0.05%
2 2025-10-24 0.12% 0.05% -0.07%
3 2025-08-28 — 0.12% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-27796

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]

Weakness enumeration for CVE-2020-27796

OS Trackers for CVE-2020-27796

vendor priority summary link
alpine high CVE-2020-27796: 1 source package rows (upx); 7 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2020-27796
debian unimportant CVE-2020-27796 unimportant priority: Debian including 1 source packages (upx-ucl), 4 status rows across 4 suites (bullseye, forky, sid, trixie): resolved 3, open 1. https://security-tracker.debian.org/tracker/CVE-2020-27796
ubuntu low CVE-2020-27796 low priority: Ubuntu including 1 source packages (upx-ucl), 13 status rows across 13 suites (bionic, focal, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): needs-triage 7, ignored 6. https://ubuntu.com/security/CVE-2020-27796

Affected software / configurations for CVE-2020-27796

Vendor Product Version Raw CPE
upx upx 4.0.0 cpe:2.3:a:upx:upx:4.0.0:*:*:*:*:*:*:*

References for CVE-2020-27796

URL Tags
https://github.com/upx/upx/issues/392 Exploit Issue Tracking Third Party Advisory
cvelogic Threat Intelligence