Vulnerability in Cisco IOS XE Software (CVE-2026-20124)
Summary
Vulnerability in Cisco IOS XE Software (CVE-2026-20124). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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.
Source: Cisco Security Advisories NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-20124 has been found in Cisco IOS XE Software.
Risk of unauthorized operations or information disclosure. CVSS score: 7.7/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Cisco IOS XE Software CVE-2026-20124" on the vendor's site.
CVE-2026-20124 (Cisco IOS XE Software) — CWE-772 / CVSS v3 7.7
Attack vector: remote (network-reachable) / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-772) exists in Cisco IOS XE Software.
Check the vendor advisory for the affected versions of Cisco IOS XE Software.
Severity: High (CVSS 7.7/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Cisco IOS XE Software を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- CISCO sec.cloudapps.cisco.com
- patch psirt@cisco.com
- web nvd.nist.gov
- web github.com