CVE-2021-26567

Stack-based buffer overflow vulnerability in frontend/main.c in faad2 before 2.2.7.1 allow local attackers to execute arbitrary code via filename and pathname options.

Published: 2021-02-26 Last update: 2025-01-14 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-26567 is rated Moderate Risk (57.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.13%). 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-2021-26567

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 2025-07-30 1.65% 1.13% -0.52%
2 2025-03-30 2.96% 1.65% -1.30%
3 2025-03-29 — 2.96% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-26567

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:L/UI:N/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:L)
A normal user session is enough; they don’t have to be admin.
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.
 1.8 5.9 [email protected]
6.5 2.0 MEDIUM
AV:N/AC:L/Au:S/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:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.0 6.4 [email protected]

Weakness enumeration for CVE-2021-26567

Affected software / configurations for CVE-2021-26567

Vendor Product Version Raw CPE
synology diskstation_manager < 6.2.3-25426-3 cpe:2.3:o:synology:diskstation_manager:*:*:*:*:*:*:*:*
synology vs960hd_firmware — cpe:2.3:o:synology:vs960hd_firmware:-:*:*:*:*:*:*:*
synology skynas_firmware — cpe:2.3:o:synology:skynas_firmware:-:*:*:*:*:*:*:*
synology diskstation_manager_unified_controller 3.0 cpe:2.3:o:synology:diskstation_manager_unified_controller:3.0:*:*:*:*:*:*:*
faad2_project faad2 < 2.2.7.1 cpe:2.3:a:faad2_project:faad2:*:*:*:*:*:*:*:*

References for CVE-2021-26567

cvelogic Threat Intelligence