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CVE-2026-76505

HIGHCVSS 7.5/10

Last modified

CVE-2026-76505 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.

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.

Metrics

CVSS 3.1
7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
CiscoCisco IOS XR Software7.0.1; 7.1.1; 7.0.90; 6.7.1; 7.0.2; 7.1.15; 7.1.2; 6.7.2; 7.1.25; 7.1.3; 6.7.3; 7.3.1; 7.4.1; 6.8.1; 7.3.2; 7.5.1; 7.6.1; 7.5.2; 7.3.3; 6.8.2; 7.7.1; 7.4.2; 7.3.4; 6.7.35; 6.9.1; 7.6.2; 7.8.1; 7.5.3; 7.7.2; 6.9.2; 7.9.1; 7.8.2; 7.5.4; 7.8.22; 7.10.1; 7.9.2; 7.3.5; 7.5.5; 7.11.1; 7.9.21; 7.10.2; 24.1.1; 7.11.2; 24.2.1; 24.1.2; 24.3.1; 24.4.1; 24.2.2; 7.8.23; 7.11.21; 24.3.2; 24.3.20; 24.3.30

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-76505?
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.
How severe is CVE-2026-76505?
CVE-2026-76505 has a CVSS score of 7.5/10 (HIGH severity).
How do I fix CVE-2026-76505?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST