How severe is CVE-2021-4459?

CVE-2021-4459 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-4459 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2021-4459?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2021-4459 have an EU (EUVD) identifier?

Yes. CVE-2021-4459 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34684.

When was CVE-2021-4459 published?

CVE-2021-4459 was published on 2025-08-27 and last updated on 2026-06-17.

CVE-2021-4459

CVE-2021-4459 is a medium-severity vulnerability with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-23.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 1% (45th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2021-34684
Weakness: CWE-23
Published: 2025-08-27
Last modified: 2026-06-17

Description

An authorized remote attacker can access files and directories outside the intended web root, potentially exposing sensitive system information of the affected Sunny Boy devices.

Frequently asked questions

What is CVE-2021-4459?: An authorized remote attacker can access files and directories outside the intended web root, potentially exposing sensitive system information of the affected Sunny Boy devices.
How severe is CVE-2021-4459?: CVE-2021-4459 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-4459 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2021-4459?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2021-4459 have an EU (EUVD) identifier?: Yes. CVE-2021-4459 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34684.
When was CVE-2021-4459 published?: CVE-2021-4459 was published on 2025-08-27 and last updated on 2026-06-17.

References

https://certvde.com/en/advisories/VDE-2025-066

Other CWE-23 vulnerabilities

CVE-2026-52813 — Critical (CVSS 10.0): Gogs is an open source self-hosted Git service. Prior to 0.14.3, organization names containing path traversal sequences…
CVE-2026-8326 — Critical (CVSS 10.0): Path traversal vulnerability in Remote Spark (https://www.Remotespark.Com/) SparkView allows reading and writing…
CVE-2026-33494 — Critical (CVSS 10.0): ORY Oathkeeper is an Identity & Access Proxy (IAP) and Access Control Decision API that authorizes HTTP requests based…
CVE-2023-3941 — Critical (CVSS 10.0): Relative Path Traversal vulnerability in ZkTeco-based OEM devices allows an attacker to write any file on the system…
CVE-2024-24578 — Critical (CVSS 10.0): RaspberryMatic is an open-source operating system for HomeMatic internet-of-things devices. RaspberryMatic / OCCU prior…
CVE-2012-6069 — Critical (CVSS 10.0): The CoDeSys Runtime Toolkit’s file transfer functionality does not perform input validation, which allows an…

Browse all CWE-23 vulnerabilities →