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TI-2021-19143 Aliases CVE-2021-43083GHSA-f935-qq4f-pj9f

Apache PLC4X 0.9.0 Buffer overflow in PLC4C via crafted server response

Priority MEDIUM 42CWE-119Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-119 and the CVSS impact.

Summary

Apache PLC4X - PLC4C (Only the C language implementation was effected) was vulnerable to an unsigned integer underflow flaw inside the tcp transport. Users should update to 0.9.1, which addresses this issue. However, in order to exploit this vulnerability, a user would have to actively connect to a mallicious device which could send a response with invalid content. Currently we consider the probability of this being exploited as quite minimal, however this could change in the future, especially with the industrial networks growing more and more together.

Why it matters now

EPSS 0.01985 80th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
ApacheApache PLC4XPLC4C – 0.9.0—No fix listedCNA
  • Apache PLC4X VendorApache Affected PLC4C – 0.9.0 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:apache:plc4x:*:*:*:*:*:*:*:*before 0.9.1VulnerableApache
  • cpe:2.3:a:apache:plc4x:*:*:*:*:*:*:*:* Versions before 0.9.1 Vulnerable ·Apache

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-43083
  2. 2026-10-03 Alias added: GHSA-f935-qq4f-pj9f

References

Advisory 2

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences