CVE-2026-20124Cisco IOS XE Software SNMP Denial of Service Vulnerability
- 7.7HighCVSS base score
- 0.50%Exploitation in 30 daysEPSS · top 57% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS XE Software could allow an authenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to improper error handling when parsing SNMP requests. This vulnerability affects all versions of SNMP — Versions 1, 2c, and 3. An attacker could exploit this vulnerability by sending a malformed SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly. The attacker must have the SNMPv1 or v2c read-only or read-write community string or valid SNMPv3 user credentials on the affected device.
Timeline
ID reserved
By cisco
- 10 months later
· 10 months later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| ciscoCNA (assigner) | 3.1 | High7.7 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H |
| NVDNVD · Analyzed | 3.1 | High7.7 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.50% · top 57% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.7.
Affected products
- affected 17.2.1a
- affected 3.18.7SP
- affected 16.12.1y
- affected 16.12.3s
- affected 16.7.1b
- affected 16.6.2
- affected 16.6.5
- affected 16.12.1w
- affected 3.18.4S
- affected 16.9.1d
- affected 17.3.1
- affected 16.9.4c
- affected 16.7.1
- affected 17.2.1
- affected 16.6.8
- affected 16.9.1b
- affected 3.16.8S
- affected 16.9.2s
- affected 16.12.4
- affected 16.12.3a
- affected 17.1.1s
- affected 16.11.1a
- affected 16.7.2
- affected 16.11.1b
- affected 16.9.1s
- affected 16.9.3h
- affected 16.9.1c
- affected 16.6.5a
- affected 16.6.3
- affected 16.10.1f
- affected 17.2.1v
- affected 16.8.1e
- affected 16.9.3a
- affected 16.12.1a
- affected 16.12.1x
- affected 3.16.10aS
- affected 16.6.4s
- affected 16.10.1c
- affected 16.12.3
- affected 16.11.2
- and 237 more
What to do
Exploitation: The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
References
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-53449 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-20124)Record last updated .