All vulnerabilities
CVE-2026-76505

Cisco IOS XR Software for ASR 9000 Series Routers IPv4 Unicast Packets Denial of Service Vulnerability

Cisco Cisco IOS XR SoftwareNetwork & edge
Open in ThreatlineRecord JSON
CVSS
7.5High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.34%Chance of exploitation activity in the next 30 days, higher than 26% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
Published21 Oct 2026Updated 22 Oct 2026CVE List

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

Vendor and government advisories 1

Vendors that say their products are affected, and agencies that issued alerts. Check each for the fixed release of the product you run.

Reports 1

1 outlet mention it. Reports are not confirmation; each links to its source.

Description

A vulnerability in the IPv4 packet processing functionality of Cisco IOS XR Software that affects Cisco ASR 9000 and 9900 Series Aggregation Services Routers as well as Cisco ASR 9902 and 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause network processor (NP) errors, resulting in a line card reset or shutdown and a denial of service (DoS) condition. 

This vulnerability is due to the incorrect handling of crafted IPv4 packets that are received on an affected line card interface and processed as for-us traffic. The issue can result in an NP reset, causing traffic loss on the affected line card while it recovers. Under repeated reset conditions, the network processor may enter a persistent shutdown state, in which case an explicit line card reload may be required to restore traffic. The vulnerability is within the IPv4 packet-processing path. Transit IPv4 traffic does not trigger this issue and IPv6 traffic cannot trigger it.

Text from CVE List

Affected versions 30

  • Cisco IOS XR Softwareaffected: 7.0.1CVE List
  • Cisco IOS XR Softwareaffected: 7.1.1CVE List
  • Cisco IOS XR Softwareaffected: 7.0.90CVE List
  • Cisco IOS XR Softwareaffected: 6.7.1CVE List
  • Cisco IOS XR Softwareaffected: 7.0.2CVE List
  • Cisco IOS XR Softwareaffected: 7.1.15CVE List
  • Cisco IOS XR Softwareaffected: 7.1.2CVE List
  • Cisco IOS XR Softwareaffected: 6.7.2CVE List
  • Cisco IOS XR Softwareaffected: 7.1.25CVE List
  • Cisco IOS XR Softwareaffected: 7.1.3CVE List
  • Cisco IOS XR Softwareaffected: 6.7.3CVE List
  • Cisco IOS XR Softwareaffected: 7.3.1CVE List
  • Cisco IOS XR Softwareaffected: 7.4.1CVE List
  • Cisco IOS XR Softwareaffected: 6.8.1CVE List
  • Cisco IOS XR Softwareaffected: 7.3.2CVE List
  • Cisco IOS XR Softwareaffected: 7.5.1CVE List
  • Cisco IOS XR Softwareaffected: 7.6.1CVE List
  • Cisco IOS XR Softwareaffected: 7.5.2CVE List
  • Cisco IOS XR Softwareaffected: 7.3.3CVE List
  • Cisco IOS XR Softwareaffected: 6.8.2CVE List
  • Cisco IOS XR Softwareaffected: 7.7.1CVE List
  • Cisco IOS XR Softwareaffected: 7.4.2CVE List
  • Cisco IOS XR Softwareaffected: 7.3.4CVE List
  • Cisco IOS XR Softwareaffected: 6.7.35CVE List
  • Cisco IOS XR Softwareaffected: 6.9.1CVE List
  • Cisco IOS XR Softwareaffected: 7.6.2CVE List
  • Cisco IOS XR Softwareaffected: 7.8.1CVE List
  • Cisco IOS XR Softwareaffected: 7.5.3CVE List
  • Cisco IOS XR Softwareaffected: 7.7.2CVE List
  • Cisco IOS XR Softwareaffected: 6.9.2CVE List

References 1