Predictable Seed in Pseudo-Random Number Generator (PRNG) in Tigo Energy Cloud Connect Advanced

published 2025-08-06 15 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-23880

cvss: 8.7; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits: 0; none known

Tigo Energy's CCA device is vulnerable to insecure session ID generation in their remote API. The session IDs are generated using a predictable method based on the current timestamp, allowing attackers to recreate valid session IDs. When combined with the ability to circumvent session ID requirements for certain commands, this enables unauthorized access to sensitive device functions on connected solar optimization systems.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-25-217-02 updated 2025-08-19 cvss 8.8

Tigo Energy Cloud Connect Advanced (Update A)

Tigo Energy Cloud Connect Advanced <=4.0.1
affected: mitigation “Tigo Energy is aware of these vulnerabilities and is actively working on a fix to address them.” support.tigoenergy.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 15 mo ago (2025-08-07)

Exploit prediction

0.61% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

Tigo Energy Cloud Connect Advanced

Classification

Weakness

CWE-337 Predictable Seed in Pseudo-Random Number Generator (PRNG)

References

cisa.gov /news-events/ics-advisories/icsa-25-217-02
government-resource

Sources

CVE List CVE-2025-7770
NVD CVE-2025-7770

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary