CVE-2021-26561

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

2.06% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 80.9% of scored records. A rank, not a probability.

NVD base score

8.1 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2021-02-26 21:45Z5 YR AGO

Last updated

2024-09-16 23:06Z2 YR AGO

Reserved

2021-02-02

Assigning CNA

synology

Record state

PUBLISHED

Severity

Critical (CVSS 9.0)

CNA CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Weaknesses

• CWE-121Stack-based Buffer OverflowVariant
• CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferClass

Data version

5.1

Document digest

722b7a6caf339b835f80cb1c12d1e8ec2ac9d6822a3b450420fb263b644aa9c5

• www.synology.comhttps://www.synology.com/security/advisory/Synology_SA_20_26x_refsource_CONFIRM
• www.talosintelligence.comhttps://www.talosintelligence.com/vulnerability_reports/TALOS-2020-1159x_refsource_MISC