Cisco IOS XR Software for ASR 9000 Series Routers IPv4 Unicast Packets Denial of Service Vulnerability
Summary
| CVE | CVE-2026-76505 |
|---|---|
| State | PUBLISHED |
| Assigner | cisco |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-21 17:19:09 UTC |
| Updated | 2026-10-21 17:19:09 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Problem Types: CWE-20 | CWE-20 Improper Input Validation
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | CVSSV3_1 | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
NoneAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Cisco | Cisco IOS XR Software | affected 7.0.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.1.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.0.90 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 6.7.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.0.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.1.15 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.1.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 6.7.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.1.25 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.1.3 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 6.7.3 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.3.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.4.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 6.8.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.3.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.5.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.6.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.5.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.3.3 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 6.8.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.7.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.4.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.3.4 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 6.7.35 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 6.9.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.6.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.8.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.5.3 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.7.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 6.9.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.9.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.8.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.5.4 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.8.22 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.10.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.9.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.3.5 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.5.5 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.11.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.9.21 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.10.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 24.1.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.11.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 24.2.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 24.1.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 24.3.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 24.4.1 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 24.2.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.8.23 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 7.11.21 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 24.3.2 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 24.3.20 | Not specified |
| CNA | Cisco | Cisco IOS XR Software | affected 24.3.30 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asr9k-... | [email protected] | sec.cloudapps.cisco.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
Additional Advisory Data
Exploits
CNA: The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
There are currently no legacy QID mappings associated with this CVE.