Ios XrOperating system · Cisco
CVE-2023-20190
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA vulnerability in the classic access control list (ACL) compression feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to bypass the protection that is offered by a configured ACL on an affected device. This vulnerability is due to incorrect destination address range encoding in the compression module of an ACL that is applied to an interface of an affected device. An attacker could exploit this vulnerability by sending traffic through the affected device that should be denied by the configured ACL. A successful exploit could allow the attacker to bypass configured ACL protections on the affected device, allowing the attacker to access trusted networks that the device might be protecting. There are workarounds that address this vulnerability. This advisory is part of the September 2023 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2023 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication .
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisA legacy NVD category covering weaknesses where permissions or privileges are assigned, checked, or dropped incorrectly, so an action ends up running with more access than it should. It is an umbrella label from older records, not a single flaw. The remedy depends on the specific case, but the throughline is least privilege with explicit, checked transitions wherever privilege changes.
General guidance for the permissions, privileges & access controls class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Ios XrOperating system
< 7.3.5>= 7.5, < 7.5.4>= 7.6, < 7.8.2= 7.9CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped7.3.57.5.47.8.2
Cisco IOS XR 7.10.x (or later stable release) - the first fixed release is 7.10.1 which addresses this vulnerability
- 1. Identify all Cisco IOS XR devices in the network and note their current software versions using 'show version'
- 2. Verify the affected device is running a vulnerable version: < 7.3.5, 7.5.x through 7.5.3, 7.6.x through 7.8.1, or exactly 7.9
- 3. For each affected device, plan a maintenance window for the upgrade
- 4. Download the appropriate fixed Cisco IOS XR software release from the Cisco software download center (cisco.com)
- 5. Prior to upgrade, backup current device configuration using 'admin commit' and 'export configuration'
- 6. Upload the new IOS XR software image to the device's bootflash or flash storage
- 7. Set the boot variable to point to the new image using 'boot system flash bootflash:<imagename>'
- 8. Reload the device with 'reload' command
Generated from the published advisory — verify against the referenced sources before acting.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-20190 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-20190 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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