CVE-2021-33485
CriticalUpdated
Published: 03 August 2021
Published
03 August 2021
Modified
29 May 2026
KEV Added
—
Patch
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CVSS Score v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score
0.0039
60.7th percentile
Risk Priority
20
60% EPSS · 20% KEV · 20% CVSS
Summary
CVE-2021-33485 is a critical-severity Out-of-bounds Write (CWE-787) vulnerability in Codesys Control. Its CVSS base score is 9.8 (Critical).
Operationally, ranked in the top 39.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-20188
Vulnerability details
CODESYS Control Runtime system before 3.5.17.10 has a Heap-based Buffer Overflow.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
codesys
control
≤ 4.2.0.0 · ≤ 4.2.0.0 · ≤ 4.2.0.0
codesys
control rte
≤ 3.5.17.10 · ≤ 3.5.17.10
codesys
control runtime system toolkit
≤ 3.5.17.10
codesys
control win sl
≤ 3.5.17.10
codesys
embedded target visu toolkit
≤ 3.5.17.10
codesys
hmi
≤ 3.5.17.10
codesys
remote target visu toolkit
≤ 3.5.17.10
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
addresses: CWE-787
Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.