CVE-2020-20277

Exp

There are multiple unauthenticated directory traversal vulnerabilities in different FTP commands in uftpd FTP server versions 2.7 to 2.10 due to improper implementation of a chroot jail in common.c's compose_abspath function that can be abused to read or write to arbitrary files on the filesystem, leak process memory, or potentially lead to remote code execution.

Published: 2020-12-18 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-20277 is rated High Exploit Risk (83.4/100): CVSS Critical severity, with high exploitation likelihood (EPSS 25.25%, 98th percentile). 2 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-2020-20277

EDB-ID Source Kind Published Link
51000 exploit_db edb 2022-08-02 Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2020-20277

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 2026-06-15 40.52% 25.25% -15.27%
2 2026-06-02 39.34% 40.52% +1.17%
3 2026-04-19 — 39.34% —

Full EPSS history (38 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-20277

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
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:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
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.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2020-20277

Affected software / configurations for CVE-2020-20277

Vendor Product Version Raw CPE
troglobit uftpd >= 2.7, <= 2.10 cpe:2.3:a:troglobit:uftpd:*:*:*:*:*:*:*:*

References for CVE-2020-20277

cvelogic Threat Intelligence