Release Notes for Cisco Catalyst 8000V Edge Software, Release 26.2.x

Hardware reliability

Resilient Infrastructure Changes

As part of Cisco’s Resilient Infrastructure program and Cisco’s commitment to secure infrastructure, this release includes additional changes aimed towards continuing to make Cisco IOS XE more secure by default.

Note that some of these changes may require operational changes if you are not following secure best practices. This release includes the following changes:

The RADIUS client appends the Message-Authenticator attribute (Attribute 80 HMAC-MD5) to all outgoing Access-Request packets to mitigate cryptographic forgery and Blast-RADIUS vulnerabilities (CVE-2024-3596).

The RADIUS client drops incoming Access-Accept, Access-Reject, and Access-Challenge packets if the Message-Authenticator packet is absent or invalid. Ensure AAA servers (example, Cisco ISE) are configured to return Attribute 80.

Outbound SSH connections enforce Trust-On-First-Use (TOFU). The device prompts to verify and store remote server host keys in the known-hosts database on first connection and validates against them on subsequent sessions.

Proxy ARP is disabled by default across all routed interfaces, SVIs, and subinterfaces to reduce Layer 2 broadcast domains and prevent ARP spoofing. Configure the ip proxy-arp command explicitly if required.

The embedded web server daemon is disabled by default on factory configurations to restrict unauthenticated management access. Web UI and RESTCONF require explicit enablement of the ip http secure-server command.

The IOS XE device rejects unauthenticated NTP Mode 6 and Mode 7 control queries (monlist) to prevent NTP reflection and amplification DDoS attacks. Standard time synchronization (Modes 3 and 4) is unaffected.

Warning messages are emitted on the console and logged to syslog whenever legacy insecure protocols (telnet, ftp, tftp, http) are enabled in the configuration.

Real-time tracking of active insecure services is published to the operational database (operDB) and YANG data models, allowing management controllers (such as Cisco Catalyst Center) to monitor security compliance.

For more information, refer Resilient Infrastructure.

API experience

IPv6 day-0 onboarding with DHCPv6 prefix delegation

Adds DHCPv6-PD as an IPv6 address-discovery option in the ZTP/PnP workflow for Cisco IOS XE Catalyst SD-WAN devices. ZTP runs IPv4 and IPv6 address discovery in parallel, and IPv6 discovery can use stateful DHCPv6, SLAAC, or DHCPv6-PD.

Upgrade

Secure Router NGFW

Secure Router NGFW introduces Cisco Catalyst NGFW, a new security-application container for supported Cisco Catalyst 8000 Series Secure Routers.

In Cisco IOS XE Catalyst SD-WAN Release 26.2.1 and Cisco Catalyst SD-WAN Manager Release 26.2.1, the feature provides workflows to install Catalyst NGFW and migrate supported settings from NGFW V1 Engine (UTD) to NGFW V2 Engine (Catalyst NGFW). IPS and IDS retain their core detection and prevention behavior while using Talos Lightweight Security Package (LSP) content. The release also adds Encrypted Visibility Engine (EVE) for encrypted-flow analysis without payload decryption and introduces Snort ML inspection for supported threats. Catalyst NGFW replaces the UTD community/subscriber signature-package workflow with independently managed LSP and Vulnerability Database (VDB) packages. LSP contains Talos rules and detectors; VDB provides application, fingerprint, and enrichment information.

Ease of use

Port settings for speed, duplex, and auto-negotiation

Configures speed, duplex, and negotiation auto in a single command.

Software Reliability

Packet-Order Preservation during Tunnel Underlay Reassembly

Cisco IOS XE 26.2.1 introduces Packet-Order Preservation during tunnel underlay

reassembly that ensures a tunnel endpoint forwards completed, reassembled packets from the same traffic flow in correct order. The feature operates with packet reassembly boost mode on supported Cisco IOS XE Catalyst SD-WAN devices and Cisco SD-WAN Manager.

Ease of use

Discontiguous Subnet Mask Support for IPv4 Network Object Groups

Adds support for discontiguous subnet mask entries in IPv4 data prefixes and IPv4 network object groups used by NGFW Policy. You can use discontiguous subnet mask entries in IPv4 source and destination match conditions, rule sets, object groups, and deploy-time data prefix variables.

Ease of setup

EVPN VPWS over SRv6

This feature adds support for EVPN VPWS over SRv6 transport. EVPN VPWS uses EVPN signaling and SRv6 encapsulation to provide point-to-point Layer 2 VPN service between provider edge devices.

CUBE Features

Security

Automatic conversion of password formats into secure types

Starting with Cisco IOS XE 26.2.1, it is recommended to use Type 6 (AES) for provisioning all credentials to comply with security standards. CUBE supports auto-conversion of Type 0 or Type 7 to reversible Type 6 encryption.

Security

Security warnings for non-secure protocols

Starting with Cisco IOS XE 26.2.1, a warning message is displayed when insecure protocols such as HTTP, FTP, or TFTP are used. For CUBE, use secure alternatives such as HTTPS, SFTP, or SCP.

The ip nat translation nonpat-timeout keyword allows configuring a timeout from 0 to 536870 seconds or setting it to never.

Refer to the ip nat translation (timeout) command.

DHCP relay is always enabled by Cisco IOS and provide status verification for cellular modems

Refer to the Configuring the DHCP Client section.

Certificate hexadecimal data appears under crypto pki certificate chain in show running-config by default. Starting with Cisco IOS XE Release 26.2, configure the crypto pki certificate hidehex command hides certificate hexadecimal data from show running-config output while retaining the certificate chain and entry.

Refer to the Certificate Hexadecimal Data Output Example.

The procedure for configuring a trustpoint for EST is updated.

Refer to the Configure a trustpoint for EST section.

CSCwt10887

SDWAN edge router device crashed after attempting to push a config group

CSCwv02836

SDWAN edge router: upgrade process may report enormous "Required space"

CSCwv02835

[IOS XE] 6VPE: Locally terminated IPv6 traffic fails over BDI interface

CSCws50867

17.18/26.1: Tracker probe id set to 0 while changing Invalid DNS endpoint to endpoint-ip

CSCwt54094

C8kv queue-limits are not adjusted in the policy-map after hsec license is installed.

CSCwu03035

SDWAN edge router: UTD may silently drop large fragmented RADIUS packets

CSCwv34598

SDWAN edge router Router Reset due to PuntInject Keepalive Timeout (No Ucode File Generated)

CSCwu83262

L2TPv3 xconnect session fails to establish when the traffic traverses through IPsec tunnel interface.

CSCwt79827

IOS-XE not parsing transform payload with unknown attributes

CSCwu03372

Unexpected reload due to ftmd fault on SDWAN edge router with On‑Demand Tunnels

CSCwv23165

BFD echo packet counters report a fixed 2:1 tx/rx ratio (false 50% packet loss) on all tunnels after enabling Enhanced Application Aware Routing

CSCwu27070

Unexpected Reload in CPP Server (cpp_sp_svr) Code

CSCwt67685

SD-WAN Edge: Periodic Service Restart May Generate Crash Files

CSCwu39202

SDWAN edge router : Power reset during cEdge boot causes router to enter ROMMON

CSCwt47734

Endpoint-tracker HTTP probe sends IP address instead of FQDN in 17.15

CSCwu21490

Kernel Core Files Deleted From Flash When Incomplete Admin Tech is Generated

CSCwv60786

Intermittent issue with RRI being lost on the Flex Hub

CSCwr02102

Router intermittently loses ip address dynamically assigned to tunnel interface

CSCwr60310

SDWAN Template push or CLI config update fails due to the duplication of VTY or Async lines in the configuration

CSCwu49029

Unexpected reload on CGM (Class-Group Manager) when updated

CSCwt75037

Device in controller mode crashes with Critical process cpp_ha_top_level_server fault on fp_0_0 (rc=69)

CSCwu49303

Memory Leak in cpp_sp_svr due to Classification Objects

CSCwu61766

SDWAN edge router OMPD crash on malformed SD-WAN identity IP-to-user update from vSmart pxGrid integration

CSCwt70932

BFD session establishment failed due to ARP resolution failure.

CSCwt44263

VPN ID is not maintained after UTD feature causing ZBFW to evaluate against incorrect policy

CSCwt66413

ncsshd process fails to terminate after "no netconf" and netconf refuses connection

CSCwt56693

L2TP: Seeing "protocol l2tpv2 L2TP_CLASS_011" config getting lost with clear ppp all cli

CSCww00071

Router crashed while decrypting NAT-T IPsec traffic with CTS SGT enabled

CSCwv25887

High QFP utilization due to NAT translation timeout and concurrent translation creation causing allocator contention

CSCwt84502

Critical Process cpp_ha_top_level_server crash (rc=69) Crash after adding zone based firewall setup configuration on the router

CSCwu53168

SDWAN edge router upgrade fails with "timeout" when confd Phase 0 failure

CSCwt17412

Sessions appear as two unidirectional records instead of one bidirectional flow

CSCwv08826

SDWAN edge router : BOW in EAAR not working when tunnels are outside SLA and outside variance

CSCwv52757

UDP packets multicast destination not seen on FIA-Trace nor EPC over xconnect

CSCws68686

Application Policy: IPv6 BGP Neighborship Fails When Using Basic Policy with Default Drop Action

CSCwt16689

QFP command displays incorrect App-Probe-Class (APC) queue assignment

CSCwv61185

C8000V vdaemon may flap SD-WAN control connections with HWCERTREN when multiple vManage-signed edge certificates have identical Not Before timestamps.

CSCwv69412

1.3.6.1.4.1.9.9.86.1.6.4.1.13.x value keep stale value until execute show dspfarm all

CSCwu67470

Unexpected reload on SDWAN edge router device after changing secuity policy to none on template

CSCwt97049

Buffer Overflow in Domain Name Pattern Handling Causes Pointer Corruption and System Crash

CSCwt46462

Enable alerts for the EC genet server (Transform) dying or timing out

CSCws66553

fpmd crash seen with 17.12.6B respin image with longer soak + clear sdwan omp events

CSCwt45748

Crash while processing packet in AppNav Tunnel

CSCwu10100

Endpoint tracker is unable to determine next-hop for DNS name resolution from Dialer interface

CSCwr49368

SSE Tunnels with Cisco Secure Access are stuck in SD-WAN Configuration Database

CSCwu02842

Unexpected reload due to race condition in QoS service group configuration

CSCwt92911

Crash in OMP process during end point tracker teardown

CSCwv42272

NULL Dereference in NHRP MIB

CSCws98086

Update "reason for state change: MAX" in BFD Syslog

CSCwt25903

Not able to disable "log" feature in NGFW Policies vManage for "Drop" rules.

CSCwv71880

SD-WAN redirect-dns Destination NAT session collides with SIG tunnel IKEv2 control plane traffic

CSCws95879

ICMP TTL Expired packet sent via incorrect VRF

CSCwu76495

SDWAN: Crash while updating Adaptive QOS Session Policy due to minimal traffic size

CSCwu86821

Service-chain config modify to local svc-chain failed to delete old TLOC list action leading to packet drops

CSCwu31509

Secondary OU is not generated in CSR for SD-Routing(Autonomous mode) devices

CSCwv09160

HTTP SIG Tracker trying to resolve endpoint-api-url IP address via DNS after upgrade to 17.15.05

CSCwt94337

cpp_cp_svr crashes with SIGSEGV whle printing packet trace data

CSCwu51162

Unexpected reload on router in SDWAN CCE (Classifier and Classification Engine)

CSCwv73701

Packet reordering observed when application performance-monitor service policy enabled

CSCwu34418

QFP crash with qfp-ucode and cpp_cp_svr cores

CSCwu53407

Standalone endpoint-tracker UP recovery syslog missing intermittently on SDWAN edge router

CSCwu35982

 Router unexpectedly reloads after IKEv2 operations

CSCwr76176

BFD SD-WAN PMTUD: PMTU Converges Unexpectedly to 970 Bytes After dbg2:1 Event

CSCwu47545

Ucode Code Crash while Printing Log for FW Drop for Packet with Invalid Header

CSCwv67035

Ikev2 PPK Unable To Switch Back to PSK When 'Required' Is Used in Keyring

CSCwt56693

L2TP: Seeing "protocol l2tpv2 L2TP_CLASS_011" config getting lost with clear ppp all cli

CSCww05599

Unexpected reload due to NAT pool exhaustion

CSCwv84068

17.12.6 likely change in the SDWAN edge router code is causing the control connections failing to come up

CSCww02502

Umbrella tunnels down, reporting cdb-validate-info failed state with 401 authentication error.

CSCwv71872

CoR-SaaS custom-app endpoint-url probing on free configurable port

CSCwv61920

Standby RP Rebooting Frequently After Applying Static Named NAT Entry

CSCwv86632

IOSd crash in "Open DNS Dev-Reg" process on 17.12.6 despite CSCwp09231 fix (Umbrella device-registration UAF during config churn)

CSCwv65418

SDWAN ICMP interface tracker goes up everytime the router resolves the DNS-name configured

CSCwv91764

CSCwv91764 - 26.2 Zscaler SSE GRE:The Public IP address for every tunnels entered on the vManage doe

CSCww20413

Update outdated GeoDB in 17.18.x

CSCwu24210

SDWAN edge router .sdwaninstaller accounting for rollback files in disk space calculation

CSCww00586

UTD context with no inspection features enabled stays in Divert mode; traffic   black-holed at memif

CSCwv80846

IOSd crash in router_init due to stale PDB pname during routing process creation

CSCww00540

SDWAN edge router - 17.12.8 endpoint-tracker reports all shared-tracker tunnels Down when one tunnel fails DNS

CSCwv98085

SDWAN 17.18.2- Cli config push fails, SDWAN edge router displays Error: application communication failure> while running "show sdwan running"