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Cisco ios, improper access control: 17 records, one defect family

Cisco ios has been reported 17 separate times for the same kind of mistake, CWE-284, between 2018-10-05 and 2026-08-05. A defect family is our own grouping of the CVE corpus: every record naming one product and one weakness class, collected so a repeat is visible as a repeat. No public source publishes this, and what this page counts is how often this one product has gone wrong in this one way.

What this page is, and what it is not

The records are public. This grouping is not, and this one took more than a lookup. Every record here carries CWE-284, which matches exactly. The product name does not: the authorities wrote it 3 different ways, and no text match joins those strings, so a search for any one spelling finds a fraction of what exists and gives no sign the rest is there. Our own embedding, pro@dim2000, read those 3 groups, of 12, 3, 2 records, and found they name one product. That is how 17 records no public source connects came to be on one page, and it is the part you cannot look up. Every spelling stays printed beside its own records, because a judgement you cannot inspect is a judgement you should not cite, and if one of them is a different product this family is wrong and its count is wrong with it.

One record is an incident. 17 filings, between 2018-10-05 and 2026-08-05, all landing on the same weakness class in the same product, is a habit in what gets reported here, and a habit is something you can plan around. This is what we held on 2026-09-20.

A repeat is evidence about where to look. If you are reviewing Cisco ios, the records below say which mistake has already been found more than once, which is the cheapest place a reviewer can start. If you are asking the vendor a question, a count under one weakness class is a better question than any single record is.

What this page cannot tell you is decided by what was joined. A product name and a weakness class settled membership, so those two values are the whole of what the page asserts. Records here may sit in the same line of code or in unrelated parts of the product, and we hold no value that separates those cases. A fixed version named in one record closes that record and says nothing about the others. And nothing here describes anyone's systems, because no value in this family connects a product name to an installation.

CVE-2018-15371CVE-2018-15372CVE-2019-1759CVE-2020-3396CVE-2020-3418CVE-2020-3503CVE-2021-1625CVE-2021-34696CVE-2023-20065CVE-2025-20190CVE-2025-20316CVE-2026-20267CVE-2018-0484CVE-2024-20465CVE-2025-20137CVE-2019-15998CVE-2019-1686
Most of this family was announced at once: 12 of the 17 records arrived in a single group. The other 5 records arrived in 2 separate groups, each with its own dates.

The names the authorities used

3 different ways, each written by whoever filed the records under it. They are printed as written rather than tidied, because the tidying is the step that would hide what was merged.

cisco ios
cisco ios xe software
cisco ios xr software

Family membership: computed, pro@dim2000

What pulled them together

These records reached one family from 3 separate groups. A join on the product name alone could not see they were the same, because the authorities wrote the product and its versions differently each time. The grouping was computed by pro@dim2000.

12 recordsCVE-2018-15371, CVE-2018-15372, CVE-2019-1759, CVE-2020-3396, CVE-2020-3418, CVE-2020-3503, CVE-2021-1625, CVE-2021-34696, CVE-2023-20065…
3 recordsCVE-2018-0484, CVE-2024-20465, CVE-2025-20137
2 recordsCVE-2019-15998, CVE-2019-1686

What the records offer

1 of 17 records publish a fixed version. For the other 16, held sources name none.

The earliest was published 2018-10-05 and the latest 2026-08-05. That span is how long this product kept producing this weakness, not how long any one record took to fix.

What this page does not cover

This is a family of records that read alike. It is not a shared vulnerability, not an inventory, and not a statement that one fix closes the rest. Each record's own state, its own dates and its own receipts are on its own page.

Grouped by shared product and weakness, not by shared vulnerability. Each record's own state is on its own page.

Everything this vendor has, including records outside this family:

CVE-2018-0484Cisco IOS and IOS XE Software Secure Shell Connection on VRF VulnerabilityCWE-284
CVE-2018-15371Cisco IOS XE Software Shell Access Authentication Bypass VulnerabilityCWE-284
CVE-2018-15372Cisco IOS XE Software MACsec MKA Using EAP-TLS Authentication Bypass VulnerabilityCWE-284
CVE-2019-15998Cisco IOS XR Software NETCONF Over Secure Shell ACL Bypass VulnerabilityCWE-284
CVE-2019-1686Cisco ASR 9000 Series Aggregation Services Routers ACL Bypass VulnerabilityCWE-284
CVE-2019-1759Cisco IOS XE Software Gigabit Ethernet Management Interface Access Control List Bypass VulnerabilityCWE-284
CVE-2020-3396Cisco IOS XE Software IOx Guest Shell USB SSD Namespace Protection Privilege Escalation VulnerabilityCWE-284
CVE-2020-3418Cisco IOS XE Wireless Controller Software for the Catalyst 9000 Family Improper Access Control VulnerabilityCWE-284
CVE-2020-3503Cisco IOS XE Software Guest Shell Unauthorized File System Access VulnerabilityCWE-284
CVE-2021-1625Cisco IOS XE Software Zone-Based Policy Firewall ICMP and UDP Inspection VulnerabilityCWE-284
CVE-2021-34696Cisco ASR 900 and ASR 920 Series Aggregation Services Routers Access Control List Bypass VulnerabilityCWE-284
CVE-2023-20065no title heldCWE-284 Improper Access Control
CVE-2024-20465no title heldCWE-284 Improper Access Control
CVE-2025-20137no title heldCWE-284 Improper Access Control
CVE-2025-20190no title heldCWE-284 Improper Access Control
CVE-2025-20316no title heldCWE-284 Improper Access Control
CVE-2026-20267Cisco IOS XE Software Security Hardening ReleaseCWE-284 Improper Access Control

17 records, read from the index as it stood on 18 Oct 2026. Every row opens the record it names, and every value on that record opens its own receipt.

Everything on this page is free. Public data. Withholding it protects nothing.