EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
- •High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 8.6Exploit: None knownExposed services: Not assessed
Upgrade to Unblu Spark 8.39.3 or later, or 7.57.9 or later (from the CVE record's solution, Switzerland National Cyber Security Centre (NCSC)) — apply it.
Cross-site scripting in the embedded co-browsing feature in Unblu inc. Unblu Spark 7.0 through 7.57.7 and 8.0 through 8.39.2, on on-premises and cloud deployments, allows an unauthenticated remote attacker in the visitor role to execute arbitrary JavaScript in the browser of an agent taking part in the attacker's co-browsing session, via content of the co-browsed page that the agent's browser renders as HTML.
The JavaScript runs in the context and under the identity of the agent's session in the Agent Desk or the Single Conversation Desk.
Exploitation requires an agent to join an embedded co-browsing session with the attacker. Mobile co-apping isn't affected.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (8.6): severity, escalated by confirmed exploitation. This CVE's 8.6 is its impact severity (EG Severity), not escalated.
- EG Severity
- 8.6 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
- EG Likelihood
- 0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-27). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
Upgrade to Unblu Spark 8.39.3 or later, or 7.57.9 or later (from the CVE record's solution, Switzerland National Cyber Security Centre (NCSC)). Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it