CVE-2020-3569: Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.
Cisco IOS XR Distance Vector Multicast Routing Protocol (DVMRP) incorrectly handles Internet Group Management Protocol (IGMP) packets. Exploitation could allow an unauthenticated, remote attacker to immediately crash the IGMP process or make it consume available memory and eventually crash.
CSIRTS triage
- What
- Cisco IOS XR has a memory exhaustion vulnerability that can crash the IGMP process.
- Who is affected
- Deployments of Cisco IOS XR Software.
- Urgency
- Immediate action is required due to the critical nature of the vulnerability and its exploitation status.
- Action
- Apply the latest updates for Cisco IOS XR Software.
AI-assisted analysis generated from the source advisory — verify against the original.
⚡ Watch IOS XR Software
Get an email when a new IOS XR Software advisory drops — max one per day, one-click unsubscribe.
Details
Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2020-3569
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Exploitation confirmedCVE-2020-3569Already exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 88% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2020-3569 | coverage & exploitation status | NVD · CVE.org |
Recent advisories for Cisco IOS XR
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- high[NEW] [high] Cisco IOS XR: Multiple vulnerabilities enable unspecified attackcert-bund · 2026-09-03
- criticalCisco IOS XR Software Security Hardening Release: September 2026cisco-psirt · 2026-09-02
- highCVE-2026-20280: As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS…nvd · 2026-09-02
- criticalCVE-2026-20279: As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS…nvd · 2026-09-02
- highCVE-2026-20278: As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS…nvd · 2026-09-02
- highCVE-2026-20277: As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS…nvd · 2026-09-02
More from CISA Known Exploited Vulnerabilities
- criticalCVE-2026-82329: JFrog Artifactory Improper Authentication Vulnerability2026-09-02
- criticalCVE-2026-49869: Kestra OSS OS Command Injection Vulnerability2026-09-02
- criticalCVE-2026-59822: BerriAI LiteLLM Improper Authentication Vulnerability2026-09-02
- criticalCVE-2026-9586: Sangoma Switchvox SQL Injection Vulnerability2026-09-02
- criticalCVE-2026-83548: SonicWall SMA1000 Appliances Server-Side Request Forgery Vulnerability2026-09-02