CISCO Security Advisory
Published Date: Not specified
CVE: CVE-2026-20281
Advisory Summary
🔷 Title: Cisco Desk Phone 9800 / IP Phone 7800 & 8800 / Video Phone 8875 — SIP Web (HTTP) Denial of Service Vulnerability
⚠️ Alarms (What’s happening?)
Cisco disclosed a High-impact vulnerability affecting Cisco desk and video phones that run SIP Software. A remote attacker can trigger a DoS (Denial of Service) condition on an affected device.
- Root cause: improper memory management when the device processes HTTP packets.
- Exploit method: an attacker sends a continuous stream of crafted HTTP packets.
- Result: the device can consume memory continuously, leading to a DoS requiring manual reboot to recover.
- is registered to Cisco Unified Communications Manager (Unified CM), and
- has Web Access enabled (notably, Web Access is disabled by default).
- Cisco has released software updates to address the issue.
- No workarounds are provided.
✅ Actionable guidance (What market pros should do now)
1. Inventory & identify affected models/firmware: Desk Phone 9800, IP Phones 7800/8800, Video Phone 8875 running SIP Software.
2. Verify exposure controls: confirm whether Web Access is enabled on each device; where possible, keep it disabled.
3. Plan rapid patching: upgrade to Cisco’s fixed software versions per the advisory; prioritize endpoints in externally reachable segments.
4. Harden network reachability: restrict inbound access to phone management/web surfaces using ACLs/segmentation so crafted HTTP traffic can’t reach phones.
5. Operational readiness: ensure your call-control/telecom ops team is prepared for manual reboot contingencies if devices are impacted during the patch window.
- CVE: CVE-2026-20281
- Security Impact Rating: High
-2026-20281
Reference: Vendor Advisory