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CVE-2026-76505

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

  • High 7.5

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.

Key facts

Published
21 Oct 2026
Last changed
22 Oct 2026
Assigned by
cisco
EPSS
0.468% likely to be exploited in the next 30 days, higher than 41.061% of CVEs (scores for 15 Nov 2026)
SSVC (CISA)
Exploitation: none; Automatable: yes; Technical impact: partial

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 7.5CVSS 3.1, Highfrom the CNA (cisco)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

No explicit remediation statement is available on this page yet. Consult the original record and vendor references before choosing a fix.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
CiscoCisco IOS XR Software
  • Default status: unknown
  • 7.0.1 (affected)
  • 7.1.1 (affected)
  • 7.0.90 (affected)
  • 6.7.1 (affected)
  • 7.0.2 (affected)
  • 7.1.15 (affected)
  • 7.1.2 (affected)
  • 6.7.2 (affected)
  • 7.1.25 (affected)
  • 7.1.3 (affected)
  • 6.7.3 (affected)
  • 7.3.1 (affected)
  • 7.4.1 (affected)
  • 6.8.1 (affected)
  • 7.3.2 (affected)
  • 7.5.1 (affected)
  • 7.6.1 (affected)
  • 7.5.2 (affected)
  • 7.3.3 (affected)
  • 6.8.2 (affected)
  • 7.7.1 (affected)
  • 7.4.2 (affected)
  • 7.3.4 (affected)
  • 6.7.35 (affected)
  • 6.9.1 (affected)
  • 7.6.2 (affected)
  • 7.8.1 (affected)
  • 7.5.3 (affected)
  • 7.7.2 (affected)
  • 6.9.2 (affected)
  • 7.9.1 (affected)
  • 7.8.2 (affected)
  • 7.5.4 (affected)
  • 7.8.22 (affected)
  • 7.10.1 (affected)
  • 7.9.2 (affected)
  • 7.3.5 (affected)
  • 7.5.5 (affected)
  • 7.11.1 (affected)
  • 7.9.21 (affected)
  • 7.10.2 (affected)
  • 24.1.1 (affected)
  • 7.11.2 (affected)
  • 24.2.1 (affected)
  • 24.1.2 (affected)
  • 24.3.1 (affected)
  • 24.4.1 (affected)
  • 24.2.2 (affected)
  • 7.8.23 (affected)
  • 7.11.21 (affected)
  • 24.3.2 (affected)
  • 24.3.20 (affected)
  • 24.3.30 (affected)

Timeline

  1. 21 Oct 2026 Published

Weakness

Related coverage

References