CVE-2026-76505 is a vulnerability in Cisco Internetwork Operating System (IOS)
Published on October 21, 2026
Cisco IOS XR Software for ASR 9000 Series Routers IPv4 Unicast Packets Denial of Service Vulnerability
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.
Vulnerability Analysis
CVE-2026-76505 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
Products Associated with CVE-2026-76505
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Affected Versions
Cisco IOS XR Software:- Version 7.0.1 is affected.
- Version 7.1.1 is affected.
- Version 7.0.90 is affected.
- Version 6.7.1 is affected.
- Version 7.0.2 is affected.
- Version 7.1.15 is affected.
- Version 7.1.2 is affected.
- Version 6.7.2 is affected.
- Version 7.1.25 is affected.
- Version 7.1.3 is affected.
- Version 6.7.3 is affected.
- Version 7.3.1 is affected.
- Version 7.4.1 is affected.
- Version 6.8.1 is affected.
- Version 7.3.2 is affected.
- Version 7.5.1 is affected.
- Version 7.6.1 is affected.
- Version 7.5.2 is affected.
- Version 7.3.3 is affected.
- Version 6.8.2 is affected.
- Version 7.7.1 is affected.
- Version 7.4.2 is affected.
- Version 7.3.4 is affected.
- Version 6.7.35 is affected.
- Version 6.9.1 is affected.
- Version 7.6.2 is affected.
- Version 7.8.1 is affected.
- Version 7.5.3 is affected.
- Version 7.7.2 is affected.
- Version 6.9.2 is affected.
- Version 7.9.1 is affected.
- Version 7.8.2 is affected.
- Version 7.5.4 is affected.
- Version 7.8.22 is affected.
- Version 7.10.1 is affected.
- Version 7.9.2 is affected.
- Version 7.3.5 is affected.
- Version 7.5.5 is affected.
- Version 7.11.1 is affected.
- Version 7.9.21 is affected.
- Version 7.10.2 is affected.
- Version 24.1.1 is affected.
- Version 7.11.2 is affected.
- Version 24.2.1 is affected.
- Version 24.1.2 is affected.
- Version 24.3.1 is affected.
- Version 24.4.1 is affected.
- Version 24.2.2 is affected.
- Version 7.8.23 is affected.
- Version 7.11.21 is affected.
- Version 24.3.2 is affected.
- Version 24.3.20 is affected.
- Version 24.3.30 is affected.