Affects Microsoft Skype for Business, a widely deployed enterprise communications product; spoofing can enable organization-wide impersonation and phishing.
CVE-2026-69646
Signature verification bug in Skype for Business allows adjacent-network spoofing
Is CVE-2026-69646 being exploited?
Not confirmed. CVE-2026-69646 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.21% probability of exploitation in the next 30 days.
How severe is CVE-2026-69646?
CVE-2026-69646 is rated High with a CVSS score of 8.3. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-69646?
Yes. A fix has been recorded for CVE-2026-69646. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-69646 affect?
CVE-2026-69646 affects Microsoft Skype for Business (client and server). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-69646?
Install Microsoft update immediately; restrict LAN access to clients and monitor authentication/logs.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Adjacent-network attacker can spoof users/messages, enabling impersonation, phishing and unauthorized actions within communications.
Immediate action required
- affected>= 9319.0 and < 6.0.9319.885
- affected>= 2046.0 and < 7.0.2046.569
- affected>= 2046.0 and < 7.0.2046.879
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.