CVE-2021-34595
CVE-2021-34595 is a high-severity vulnerability in Codesys with a CVSS 3.x base score of 8.1. 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-119.
Key facts
- Severity: High (CVSS 3.x base score 8.1)
- CVSS v2: 5.5
- EPSS exploit prediction: 1% (56th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-119
- Affected product: Codesys
- Published:
- Last modified:
Description
A crafted request with invalid offsets may cause an out-of-bounds read or write access in CODESYS V2 Runtime Toolkit 32 Bit full and PLCWinNT prior to versions V2.4.7.56, resulting in a denial-of-service condition or local memory overwrite.
Frequently asked questions
- What is CVE-2021-34595?
- A crafted request with invalid offsets may cause an out-of-bounds read or write access in CODESYS V2 Runtime Toolkit 32 Bit full and PLCWinNT prior to versions V2.4.7.56, resulting in a denial-of-service condition or local memory overwrite.
- How severe is CVE-2021-34595?
- CVE-2021-34595 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
- Is CVE-2021-34595 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-34595?
- CVE-2021-34595 primarily affects Codesys. In total, 30 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2021-34595?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2021-34595 published?
- CVE-2021-34595 was published on 2021-10-26 and last updated on 2026-06-17.
References
Affected products (30)
- cpe:2.3:o:wago:750-823_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-829_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-831_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-832_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-852_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-862_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-880_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-881_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-882_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-885_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-889_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-890_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-891_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-893_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8202_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8203_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8204_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8206_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8207_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8208_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8210_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8211_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8212_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8213_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8214_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8216_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:wago:750-8217_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:a:codesys:codesys:*:*:*:*:*:*:*:*
- cpe:2.3:a:codesys:plcwinnt:*:*:*:*:*:*:*:*
- cpe:2.3:a:codesys:runtime_toolkit:*:*:*:*:*:*:x86:*
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