Cisco Stock After Hours Today (Dec. 18, 2025): CSCO Slips in Late Trading as a Critical Zero‑Day Cyber Alert Hits Headlines — What to Watch Before Friday’s Open
Cisco shares closed up 1.25% at $76.95 Thursday, then slipped about 0.4% after hours as the company confirmed active exploitation of a critical zero-day vulnerability in its Secure Email appliances. No patch was available at disclosure, and U.S. authorities flagged the issue as urgent. Trading volume reached 18.9 million shares during the regular session.