CVE-2026-20004
Cisco Cisco IOS XE Software
At a glance
- Source
- NVD
- EPSS
- EPSS 0.19 % · percentile 8 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- cisco
- NVD status
- Analyzed
Description
A vulnerability in the TLS library of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to exhaust the available memory of an affected device. This vulnerability is due to improper management of memory resources during TLS connection setup. An attacker could exploit this vulnerability by repeatedly triggering the conditions that cause the memory increase. This could be done in a variety of ways, such as by repeatedly attempting Extensible Authentication Protocol (EAP) authentication when local EAP is enabled on an affected device or by using a machine-in-the-middle attack and resetting TLS connections between the affected device and other devices. A successful exploit could allow the attacker to exhaust the available memory on an affected device, resulting in an unexpected reload and a denial of service (DoS) condition.
Weaknesses (CWE)
- CWE-771 — Missing Reference to Active Allocated Resource
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.4 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H | cisco |
| CVSS 3.1 | HIGH 7.4 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H | NVD · psirt@cisco.com (Secondary) |
European references
- ENISA EUVD · EUVD-2026-15426
- GCVE · GCVE-0-2026-20004
CERT-FR advisories
- CERTFR-2026-AVI-0361 — Multiples vulnérabilités dans Cisco IOS et IOS XE · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:cisco:ios_xe:16.9.1:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.1a:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.1b:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.1s:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.2:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.3:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.3a:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.4:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.5:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.5f:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.6:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.7:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.8:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.1:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.1a:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.1b:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.1c:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.1d:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.1e:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.1f:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.1g:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.1s:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.2:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.3:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.11.1:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.11.1a:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.11.1b:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.11.1s:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.11.2:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1a:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1c:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1s:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1t:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1w:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1x:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1y:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1z1:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1z2:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.2:*:*:*:*:*:*:*- +140 more
Affected products
| Product | Versions |
|---|---|
| Cisco · Cisco IOS XE Software | affected 16.9.1 ; affected 16.9.2 ; affected 16.9.1a ; affected 16.9.1b ; affected 16.9.1s ; affected 16.9.3 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |