Cyber Resilience

CVE-2025-43976

Access Control in Textnow 2Ndline 24.17.1.0

Public PoCAccess Control
Published
21 July 2025
Modified
17 June 2026
Patch / advisory
CVSS Score v3.1 5.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
EPSS Score 0.0019 8th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2025-43976 is a medium-severity Missing Authorization (CWE-862) vulnerability in Textnow 2Ndline. Its CVSS base score is 5.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-6 (Least Privilege) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

The com.enflick.android.tn2ndLine application through 24.17.1.0 for Android enables any installed application (with no permissions) to place phone calls without user interaction by sending a crafted intent via the com.enflick.android.TextNow.activities.DialerActivity component.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1559 Inter-Process Communication Execution
Adversaries may abuse inter-process communication (IPC) mechanisms for local code or command execution.
Why these techniques?

The vulnerability enables any installed app to exploit insecure intent handling in the TextNow DialerActivity (CVE-2025-43976) to silently execute phone calls without permissions or user interaction, facilitating T1203 (Exploitation for Client Execution) via client app vuln exploitation and T1559 (Inter-Process Communication) via abuse of Android IPC intents.

CVEs Like This One

CVE-2025-31736Shared CWE-862
CVE-2024-9109Shared CWE-862
CVE-2023-37887Shared CWE-862
CVE-2025-47688Shared CWE-862
CVE-2024-1732Shared CWE-862
CVE-2024-54269Shared CWE-862
CVE-2023-38475Shared CWE-862
CVE-2025-31786Shared CWE-862
CVE-2025-31862Shared CWE-862
CVE-2025-28103Shared CWE-862

Affected Assets

textnow
2ndline
24.17.1.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • AC-3 Access Enforcement
  • AC-6 Least Privilege
  • AC-4 Information Flow Enforcement
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly requires the DialerActivity component to enforce authorization checks before allowing any app to invoke call placement via crafted intents.

prevent

Requires the exported activity to operate with least privilege so that no-permission apps cannot reach privileged telephony functions.

prevent

Enforces mediation of information flows between Android apps, blocking unauthorized intent-based IPC to the dialer component.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 full match
prevents

Explicitly requires defining, enforcing, and reviewing authorizations and least privilege, directly preventing missing authorization checks.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Requiring authentication and credentials before any access occurs eliminates the absence of authorization checks that would otherwise allow an unauthenticated actor to reach protected resources.

prevents

Requiring formal authorization of every access request before rights are granted ensures that checks for required permissions are performed, preventing missing authorization checks from being introduced.

prevents

Mandatory authorization checks and central records of granted rights ensure that every access attempt is preceded by an explicit decision rather than relying on missing checks.

mitigates

Segregating the approval of access rights from their implementation provides an independent check that reduces the impact of missing authorization checks in the resulting system configuration.

detects

By requiring competent outsiders to verify that every function enforces the need-to-know principle, the control lowers the likelihood that missing authorization checks persist undetected.

prevents

Defining authorization responsibilities and reviewing risk-treatment progress throughout the project lifecycle catches missing authorization checks before the system is deployed.

References