CVE-2026-3869: Incorrect Implementation of Authentication Algorithm in PLC
A NVD · · CVE-2026-3869
Admiralty grading (A–F · 1–6)
Source reliability
- A Completely reliable
- B Usually reliable
- C Fairly reliable
- D Not usually reliable
- E Unreliable
- F Cannot be judged
Information credibility
- 1 Confirmed
- 2 Probably true
- 3 Possibly true
- 4 Doubtful
- 5 Improbable
- 6 Cannot be judged
NATO Admiralty (AJP-2.1) grades confidence, independent of the risk score. Cross-source corroboration isn't tracked for non-CVE news, so single-source items are capped at a lower credibility number; a low number does not imply low quality.
Key metrics
- EPSS
- 0%
Key insight
The vulnerability enables authentication bypass in PLC systems through incorrect implementation of authentication algorithms, which is particularly critical for legacy or lower application levels.
Description
CVE-2026-3869 describes an authentication implementation vulnerability in programmable logic controllers (PLCs). The vulnerability is caused by incorrect implementation of an authentication algorithm (CWE-303) and could allow an attacker to compromise the confidentiality, integrity, and availability of the PLC system. Exploitation requires that an application project with a lower application level is running on the PLC. The vulnerability has been registered in the NVD; active exploitation status is not fully documented.
Risk score
- cvss base
- 0.00
- kev bonus
- 0.00
- epss bonus
- 0.00
- poc bonus
- 0.00
- raw before weight
- 0.00
- industry weight
- 1.10
- freshness factor
- 1.00
- exploitability factor
- 1.00
- days old
- 0.00
- vendor mismatch penalty
- 0.00
Path: operational