Executive brief
A vulnerability in Cisco IOS XE's SNMP subsystem can be exploited by an authenticated attacker with SNMP credentials to crash the network device, causing temporary unavailability. An attacker with valid SNMP community strings or user credentials can send a specially crafted SNMP request that triggers improper error handling, forcing the affected device to reload. This impacts network availability and could disrupt critical operations on affected routers or switches.
Technical details
The vulnerability is a denial of service flaw (CWE-772) in the SNMP subsystem's error handling logic when parsing malformed SNMP requests. It affects all SNMP versions (1, 2c, and 3). An attacker must be authenticated with valid SNMPv1/v2c community strings (read-only or read-write) or valid SNMPv3 user credentials to exploit this vulnerability. The attack vector is network-based, and a successful exploit causes an unexpected device reload. Cisco has released software patches; no workarounds are available, though temporary mitigation via OID exclusion is possible.
Affected products
- Cisco IOS XE Software <UNKNOWN>
Timeline
- 2026-08-05: disclosed: Cisco security advisory published
- 2026-08-05: other: Cisco Bug ID CSCws90638