Cisco IOS XR Border Gateway Protocol (BGP) Denial-of-Service Vulnerability
Cisco IOS XR 3.4.0 through 3.8.1 allows remote attackers to cause a denial of service (session reset) via a BGP UPDATE message with an invalid attribute, as demonstrated in the wild on 17 August 2009.
Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.
Exploitation probability EPSS · FIRST
Exploitation signals 3 / 5
- KEV catalog (CISA)25 Mar 2022
- Exploited in EUVD (ENISA)25 Mar 2022
- Used by ransomwareno
- EPSS above 10 %3.3%
- No account, over the networkyes
What to do
Fix
Apply the vendor’s fix as soon as it is available.
CISA guidance: Apply updates per vendor instructions.
Meanwhile
Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.
Manufacturers (CRA)
Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained
Affected products
Open source packages OSV
Affected libraries according to OSV, with fixed versions.
Timeline
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Published
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Exploitation reported (ENISA)
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Added to the KEV catalog
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CISA remediation due date
References
Other exploited vulnerabilities from the same vendor
- CVE-2026-76418Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability5.3 · Rising fast
- CVE-2026-76519Cisco Secure Email Gateway Relative Path Traversal Vulnerability5.8 · Rising fast
- CVE-2026-76504Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability7.5 · Actively exploited
- CVE-2026-76460Cisco Identity Services Engine Incorrect Use of Privileged APIs Vulnerability8.7 · Actively exploited
- CVE-2026-76461Cisco Secure Email Gateway SQL Injection Vulnerability7.2 · Actively exploited
- CVE-2026-20079Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel Vulnerability9.1 · Actively exploited