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CVE-2026-76505

7.5, high

Cisco IOS XR Software Improper Input Validation Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab)
CVSS
7.5, high high CVSS v3.1
EPSS, next 30 days
0.3% higher than 26.4% of scored CVEs
Exploitation
No public evidence
Published
21 Oct 20262 days ago

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.

Details

Vendor
Cisco
Product
Cisco IOS XR Software
Weakness
CWE-20 (opens in a new tab)
Status
Awaiting analysis
Updated
21 Oct 2026
Assigner
psirt@cisco.com

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

References 1

Advisories 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Cisco CVEs

Every Cisco CVE we hold

Same vendor in what we hold, not a known link between the flaws.

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  • CVE-2026-76504 Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability KEV EPSS 2% 9.8, critical
  • CVE-2026-76460 Cisco Identity Services Engine Incorrect Use of Privileged APIs Vulnerability KEV EPSS 14% 10, critical
  • CVE-2026-76461 Cisco Secure Email Gateway SQL Injection Vulnerability KEV EPSS 30% 9.8, critical
  • CVE-2026-20349 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection Vulnerability KEV EPSS 1% 8.6, high
  • CVE-2026-20316 Cisco Secure Firewall Management Center Use of Hard-coded Password Vulnerability KEV EPSS 35% 5.3, medium
  • CVE-2026-20262 Cisco Catalyst SD-WAN Manager Directory or Path Traversal Vulnerability KEV EPSS 28% 6.5, medium
  • CVE-2026-20245 Cisco Catalyst SD-WAN Manager Improper Encoding or Escaping of Output Vulnerability KEV EPSS 25% 7.8, high

Beyond this page

Is CVE-2026-76505 in your network?

This page tells you how dangerous CVE-2026-76505 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

  • EXYS7600 OCELOT

    Find it before attackers do

    Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2026-76505 comes with the devices to patch.

    Learn more about EXYS7600 OCELOT

  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

    Learn more about EXYS7950 KONDRA
Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 23 Oct 2026, not the live upstream state.