Cisco IOS XR IPv4 DoS

Cisco IOS XR

Unauthenticated remote attacker can cause network processor errors, resulting in a denial of service condition.

Do this now

Apply the Cisco IOS XR fix for the IPv4 denial-of-service issue.

Still cooking for Cisco IOS XR Software.

First seen: 21 Oct 2026
Last update: 21 Oct 2026, 16:00 UTC
Identifiers: CVE-2026-76505
CVSS: 7.5
Source: news
On the menu as: VPN & firewalls

Check this repository for exposure to one security incident from pwned.coffee. Report first, change nothing until I say so.

## Cisco IOS XR IPv4 DoS
Severity: high. Patch status: patched.
Affected: Cisco IOS XR
Ids: CVE-2026-76505

Unauthenticated remote attacker can cause network processor errors, resulting in a denial of service condition.

## Steps
1. This touches infrastructure (vpn-edge). Look in terraform, ansible, cloud-init, Dockerfiles and docs for the product and version we run. If it isn't in the repo, say so and list what a human should check on the box.

## Report
A table: file, product or package, version in use, affected yes/no, exact fix. Then anything a human has to check outside the repo.

If you have the pwned.coffee MCP server (https://pwned.coffee/mcp), call lookup_cve("CVE-2026-76505") for the latest, and check_repo with this repo's lockfiles, Dockerfiles and workflows for a full receipt.
Sources: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asr9k-tUyxcyXN?vs_f=Cisco%20Security%20Advisory%26vs_cat=Security%20Intelligence%26vs_type=RSS%26vs_p=Cisco%20IOS%20XR%20Software%20for%20ASR%209000%20Series%20Routers%20IPv4%20Unicast%20Packets%20Denial%20of%20Service%20Vulnerability%26vs_k=1
https://pwned.coffee/i/cisco-ios-xr-ipv4-dos-cve-2026-76505

Receipt

Exploitation: No known exploitation
Fix by release line: Product Affected Fixed in Source
Cisco IOS XR Software = 24.4.1 no fix on 24.4.x yet CVE record (CNA)
Cisco IOS XR Software 24.3.1 to now no fix on 24.3.x yet CVE record (CNA)
Cisco IOS XR Software 24.2.1 to now no fix on 24.2.x yet CVE record (CNA)
Cisco IOS XR Software 24.1.1 to now no fix on 24.1.x yet CVE record (CNA)
Cisco IOS XR Software 7.11.1 to now no fix on 7.11.x yet CVE record (CNA)
Cisco IOS XR Software 7.10.1 to now no fix on 7.10.x yet CVE record (CNA)
Cisco IOS XR Software 7.9.1 to now no fix on 7.9.x yet CVE record (CNA)
Cisco IOS XR Software 7.8.1 to now no fix on 7.8.x yet CVE record (CNA)
Cisco IOS XR Software 7.7.1 to now no fix on 7.7.x yet CVE record (CNA)
Cisco IOS XR Software 7.6.1 to now no fix on 7.6.x yet CVE record (CNA)
Cisco IOS XR Software 7.5.1 to now no fix on 7.5.x yet CVE record (CNA)
Cisco IOS XR Software 7.4.1 to now no fix on 7.4.x yet CVE record (CNA)
Score: CVSS 7.5 (high). CVSS 3.1 7.5 (CNA cisco) for CVE-2026-76505
Last checked: 24 Oct 2026, 18:17 UTC

Product	Affected	Fixed in	Source
Cisco IOS XR Software	= 24.4.1	no fix on 24.4.x yet	CVE record (CNA)
Cisco IOS XR Software	24.3.1 to now	no fix on 24.3.x yet	CVE record (CNA)
Cisco IOS XR Software	24.2.1 to now	no fix on 24.2.x yet	CVE record (CNA)
Cisco IOS XR Software	24.1.1 to now	no fix on 24.1.x yet	CVE record (CNA)
Cisco IOS XR Software	7.11.1 to now	no fix on 7.11.x yet	CVE record (CNA)
Cisco IOS XR Software	7.10.1 to now	no fix on 7.10.x yet	CVE record (CNA)
Cisco IOS XR Software	7.9.1 to now	no fix on 7.9.x yet	CVE record (CNA)
Cisco IOS XR Software	7.8.1 to now	no fix on 7.8.x yet	CVE record (CNA)
Cisco IOS XR Software	7.7.1 to now	no fix on 7.7.x yet	CVE record (CNA)
Cisco IOS XR Software	7.6.1 to now	no fix on 7.6.x yet	CVE record (CNA)
Cisco IOS XR Software	7.5.1 to now	no fix on 7.5.x yet	CVE record (CNA)
Cisco IOS XR Software	7.4.1 to now	no fix on 7.4.x yet	CVE record (CNA)

Sources: KEV – CVE record ✓ Vendor ✓

Sources

sec.cloudapps.cisco.com: Cisco IOS XR Software for ASR 9000 Series Routers IPv4 Unicast Packets Denial of Service Vulnerability

Totalone hot coffee