Security readout for executives and security teams
Plain-English summary
CVE-2021-34735 affects Cisco ATA 190 Series analog telephone adapter software. The reported impact is serious: an attacker with low privileges could potentially run commands on the device or cause a denial of service. For organizations using these adapters for voice services, the business risk is service disruption and possible device compromise.
Executive priority
Treat this as high priority where Cisco ATA 190 Series devices support business voice services. The main urgency is reducing the chance of device compromise or phone-service disruption, especially on exposed or poorly segmented networks.
Technical view
Cisco describes multiple vulnerabilities in ATA 190 Series Analog Telephone Adapter Software that could allow command injection resulting in remote code execution or denial of service. CVSS v3.1 is 8.8, with network attack vector, low privileges required, no user interaction, unchanged scope, and high confidentiality, integrity, and availability impact. CWE-770 is listed.
Likely exposure
Exposure is likely limited to organizations operating Cisco ATA 190 Series devices with affected software. Internet-facing management or weakly segmented voice networks would raise concern, but the bundle does not identify exact vulnerable versions or deployment conditions.
Exploitation context
The source bundle does not cite CISA KEV inclusion or any active exploitation evidence. The CVSS vector indicates exploitation is network-based and requires low privileges, with no user interaction. Do not treat it as confirmed exploited based on these sources alone.
Researcher notes
Evidence is limited to the CVE metadata and Cisco advisory reference in the bundle. The bundle confirms impact class and CVSS characteristics but does not provide affected version ranges, exploit details, observed exploitation, or named fixed releases.
Mitigation direction
- Review Cisco’s advisory for fixed software and supported remediation guidance.
- Inventory Cisco ATA 190 Series devices and record software versions.
- Restrict device management access to trusted administrative networks.
- Monitor voice infrastructure for unexpected reboots, outages, or configuration changes.
- Prioritize replacement or isolation if vendor-supported fixes are unavailable.
Validation and detection
- Confirm whether Cisco ATA 190 Series devices exist in the environment.
- Compare installed software versions against Cisco’s advisory guidance.
- Verify management interfaces are not exposed to untrusted networks.
- Check logs for suspicious administrative activity or unexplained service interruptions.
- Document compensating controls for any device that cannot be updated promptly.
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-770: 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-34735 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
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20211006 Cisco ATA 190 Series Analog Telephone Adapter Software VulnerabilitiesCVE 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.
Allocation of Resources Without Limits or Throttling
Allocation of Resources Without Limits or Throttling represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.