Security readout for executives and security teams
Plain-English summary
This is a medium-severity information disclosure issue in Cisco IOS XR. A lower-privileged authenticated local user could see sensitive configuration information they should not access. It does not describe remote unauthenticated compromise, but it matters for network devices where shared administrative access or delegated CLI roles are used.
Executive priority
Treat as a moderate network infrastructure risk. Prioritize environments with shared router administration, outsourced operations, or many delegated network users. It is mainly a confidentiality issue, but exposed device configuration can materially aid later attacks.
Technical view
Cisco describes insufficient restriction enforcement in the IOS XR CLI during execution of a specific command. The CVSS 3.1 vector is local, low complexity, low privileges, no user interaction, unchanged scope, and high confidentiality impact only. Affected version detail is not present in the supplied bundle.
Likely exposure
Organizations running Cisco IOS XR Software with local or delegated CLI users may be exposed. Exposure cannot be scoped to specific versions from the supplied data because affected versions are listed as n/a.
Exploitation context
The bundle supports an authenticated local attack path only. The attacker must already have low-privileged access to the IOS XR CLI. CISA KEV is false, and no cited source here supports active exploitation.
Researcher notes
The strongest evidence is Cisco's description and CVSS vector. Do not assume remote exploitability, privilege escalation, or active exploitation. Version and fixed-release details are incomplete in the supplied bundle, so validation depends on Cisco advisory review.
Mitigation direction
- Review Cisco's advisory for affected releases and vendor-recommended fixes.
- Limit IOS XR CLI access to trusted administrators only.
- Apply least-privilege roles for network operations accounts.
- Audit shared or low-privileged local accounts on IOS XR devices.
- Monitor vendor guidance before making operational changes.
Validation and detection
- Inventory Cisco IOS XR Software deployments and versions.
- Compare deployed versions against Cisco's advisory.
- Identify users with local or delegated IOS XR CLI access.
- Review whether sensitive configuration access is properly restricted.
- Check change and access logs for unexpected low-privileged CLI activity.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-201: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-34771 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N1.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.5MediumVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20210908 Cisco IOS XR Software Unauthorized Information Disclosure VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Insertion of Sensitive Information Into Sent Data
Insertion of Sensitive Information Into Sent Data represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.