Security readout for executives and security teams
Plain-English summary
This flaw lets a logged-in local attacker use a Cisco IP Phone debug shell to read any file on the phone. It is not a remote internet-scale issue from the cited data, but it can expose sensitive device data where attackers already have local authenticated access.
Executive priority
Treat this as a targeted confidentiality risk, not an emergency internet-wide exposure. Prioritize remediation for environments where phones are physically accessible, shared, or used in sensitive areas.
Technical view
CVE-2021-34711 is an arbitrary file read in Cisco IP Phone Software debug shell input handling. The issue is insufficient input validation, classified as CWE-36. CVSS 3.1 is 5.5: local attack vector, low complexity, low privileges, no user interaction, high confidentiality impact, no integrity or availability impact.
Likely exposure
Exposure is limited to Cisco IP Phones with Multiplatform Firmware where an attacker can authenticate locally and reach the debug shell. The source bundle does not provide specific affected version ranges.
Exploitation context
The provided sources do not report active exploitation, and the CVE is not marked CISA KEV. Exploitation requires authenticated local access and crafted input to a debug shell command; no public exploit status is established in the bundle.
Researcher notes
The key constraints are local access, low privileges, and debug shell reachability. The source bundle identifies the affected product family but not detailed version ranges or named fixed releases, so validation should anchor on Cisco’s advisory.
Mitigation direction
- Review Cisco’s advisory for affected and fixed firmware guidance.
- Inventory Cisco IP Phones running Multiplatform Firmware.
- Restrict local and debug-shell access to trusted administrators.
- Prioritize remediation where phones are in shared or weakly controlled locations.
Validation and detection
- Confirm whether Cisco IP Phones with Multiplatform Firmware are deployed.
- Map deployed firmware against Cisco’s advisory guidance.
- Review who can authenticate locally to affected phones.
- Check operational controls around physical access to phone hardware.
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-36: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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 lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-34711 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
- 20211006 Cisco IP Phone Software Arbitrary File Read 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.
Absolute Path Traversal
Absolute Path Traversal represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.