Johnson Controls ICS CVE-2025-61739

Exploitation requires the attacker to occupy an adjacent/local network position (CVSS AV:A) relative to the affected Johnson Controls device so that encrypted traffic can be intercepted or injected - this cannot be performed remotely over the internet without such access. Given PR:N and UI:N, no authentication or victim interaction is needed once the attacker is on the network. The core flaw is cryptographic nonce reuse (CWE-323) in the product's encrypted communications, which permits replaying previously captured packets and/or decrypting captured ciphertext. The primary limiting factor is the adjacency requirement (same L2 segment/local network); the specific affected product, version, and whether any particular communication mode or feature must be in use are not specified in the provided data and should be confirmed against the Johnson Controls advisory and CISA ICSA-25-350-02.

This is a genuine but bounded risk, best characterized as a HIGH-severity (CVSS 4.0 base 7.2) cryptographic weakness whose real-world exploitability is constrained by network positioning rather than configuration. The CVSS vector reports adjacent-network access (AV:A), low complexity (AC:L), no privileges (PR:N) and no user interaction (UI:N), with impact weighted toward integrity (VI:H) over confidentiality (VC:L) and availability (VA:L) - consistent with CWE-323 (nonce reuse) enabling both replay (integrity) and limited packet decryption (confidentiality). Signals are coherent and point toward MODERATE priority: EPSS is low at 0.19% (8th percentile), there is no CISA KEV listing and no public exploit identified, so there is no evidence of active or widespread exploitation. No SSVC decision data was provided in the input. The AV:A requirement is the dominant limiting factor - an attacker must already be on the same local/adjacent network segment to capture traffic, which rules out remote internet-based mass exploitation and makes this most relevant to insider, lateral-movement, or physically-proximate threat models typical of ICS/building-automation environments. Net: prioritize patching for exposed or flat OT networks, but this is not an internet-facing drop-everything emergency given the adjacency constraint and low EPSS.

An attacker with a foothold on the same local/adjacent network segment as the affected Johnson Controls device passively captures its encrypted traffic. Because the same nonce is reused during encryption (CWE-323), the attacker can replay captured packets to repeat prior commands/transactions or perform cryptanalysis to decrypt sensitive captured data. No public proof-of-concept exploit was identified in the provided intelligence, and exploitation requires adjacent-network access rather than remote reachability.