CVE-2021-26620 | IPTIME NAS2dual improper authentication vulnerability

An improper authentication vulnerability leading to information leakage was discovered in iptime NAS2dual. Remote attackers are able to steal important information in the server by exploiting vulnerabilities such as insufficient authentication when accessing the shared folder and changing user’s passwords.

Published: 2022-03-25 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-26620 is rated Moderate Risk (54.3/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.61%). Review affected assets and schedule remediation.

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

Exploit prediction scoring system (EPSS) score for CVE-2021-26620

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 2025-11-21 0.41% 0.61% +0.20%
2 2025-11-18 0.61% 0.41% -0.20%
3 2025-04-10 — 0.61% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-26620

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N 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:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N 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:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N 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:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-26620

Affected software / configurations for CVE-2021-26620

Vendor Product Version Raw CPE
iptime nas101_firmware < 1.4.82 cpe:2.3:o:iptime:nas101_firmware:*:*:*:*:*:windows:*:*
iptime nas1dual_firmware < 1.4.82 cpe:2.3:o:iptime:nas1dual_firmware:*:*:*:*:*:windows:*:*
iptime nas2dual_firmware < 1.4.82 cpe:2.3:o:iptime:nas2dual_firmware:*:*:*:*:*:windows:*:*
iptime nas3_firmware < 1.4.82 cpe:2.3:o:iptime:nas3_firmware:*:*:*:*:*:windows:*:*
iptime nas4_firmware < 1.4.82 cpe:2.3:o:iptime:nas4_firmware:*:*:*:*:*:windows:*:*
iptime nas4dual_firmware < 1.4.82 cpe:2.3:o:iptime:nas4dual_firmware:*:*:*:*:*:windows:*:*
iptime nas-i_firmware < 1.4.82 cpe:2.3:o:iptime:nas-i_firmware:*:*:*:*:*:windows:*:*
iptime nas-ii_firmware < 1.4.82 cpe:2.3:o:iptime:nas-ii_firmware:*:*:*:*:*:windows:*:*
iptime nas-iie_firmware < 1.4.82 cpe:2.3:o:iptime:nas-iie_firmware:*:*:*:*:*:windows:*:*

References for CVE-2021-26620

cvelogic Threat Intelligence