Medium6.8Vendor: HighCisco Exploited

Medium [CVE-2026-20118] Cisco IOS XR Egress Packet Network Interface Aligner Interrupt Denial of Service Vulnerability

This medium-severity Cisco advisory covers CVE-2026-20118 affecting Cisco IOS XR Software.

cisco-sa-xrncs-epni-int-dos-TWMffUsN Published Mar 11, 2026Updated by vendor Mar 11, 2026

CVE-2026-20118

Affected products & platforms

CiscoRouters

Open vendor advisory

Android app · Google Play

Monitor future Cisco CVEs from your phone.

Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 32 official vendor sources and 160+ reviewed platform categories.

Matching phone alertsOptional email delivery

Get CVE alerts See app features

Summary

A vulnerability in the handling of an Egress Packet Network Interface (EPNI) Aligner interrupt in Cisco IOS XR Software for Cisco Network Convergence System (NCS) 5500 Series with NC57 line cards and Cisco NCS 5700 Routers and Cisco IOS XR Software for Third Party Software could allow an unauthenticated, remote attacker to cause the network processing unit (NPU) and ASIC to stop processing, preventing traffic from traversing the interface.

This vulnerability is due to the corruption of packets in specific cases when an EPNI Aligner interrupt is triggered while an affected device is experien…

Affected versions

Scope: This vulnerability affects the following Cisco products if they are running a vulnerable release of Cisco IOS XR Software, regardless of the device configuration:
Release 7.8.2 and earlier (first fixed: Not affected)
7.9 — Migrate to a fixed release or apply SMU
7.10 — Migrate to a fixed release or apply SMU
7.11 — Migrate to a fixed release or apply SMU
24.1 — Migrate to a fixed release or apply SMU
24.2 — Migrate to a fixed release or apply SMU
24.3 — Migrate to a fixed release or apply SMU
24.4 — Migrate to a fixed release or apply SMU
25.1 — Migrate to a fixed release or apply SMU

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Fixed versions

Not affected

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Mitigation checklist

Recommended fix / mitigation

Upgrade to the first fixed release for your train per the Fixed Releases table in this advisory.
Release 7.8.2 and earlier: upgrade to Not affected.
Release 7.9: migrate to a fixed release or apply SMU.
Release 7.10: migrate to a fixed release or apply SMU.
Release 7.11: migrate to a fixed release or apply SMU.
Release 24.1: migrate to a fixed release or apply SMU.
Release 24.2: migrate to a fixed release or apply SMU.
Release 24.3: migrate to a fixed release or apply SMU.
Release 24.4: migrate to a fixed release or apply SMU.

Workaround status

There are no workarounds that address this vulnerability.

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Sources

Official and corroborating records used to build this advisory.

Cisco Security Advisories (PSIRT)official
Official vendor feed — the source of truth for this advisory. VulniPulse polled this feed and parsed this entry from it. Discovered from the machine-readable feed https://sec.cloudapps.cisco.com/security/center/psirtrss20/CiscoSecurityAdvisory.xml; this link opens the Cisco advisory index instead of the raw feed document.
Cisco
Vendor advisory pageofficial
Advisory page fetched and parsed to extract affected/fixed versions and mitigation guidance beyond what the feed carries.
Cisco

Cross-references

Validate CVE metadata against the authoritative registries.

CVE-2026-20118NVD CVE.org MITRE

Official resources

Cisco Software Checker
Official documentation
Official tool to confirm whether your exact IOS / IOS XE / NX-OS / ASA / FTD / SD-WAN release is affected and to find the first fixed release.

Discussion(0)

No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.