Cyber Resilience

CVE-2024-39899

Auth Bypass

Published
09 July 2024
Modified
15 April 2026
CVSS Score v3.1 5.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS Score 0.0063 47th percentile
Risk Priority 45 floored blend · peak EPSS

Summary

CVE-2024-39899 is a medium-severity Authentication Bypass by Primary Weakness (CWE-305) vulnerability. Its CVSS base score is 5.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 47th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to IA-2 (Identification and Authentication (Organizational Users)) and IA-8 (Identification and Authentication (Non-organizational Users)) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

PrivateBin is an online pastebin where the server has zero knowledge of pasted data. In v1.5, PrivateBin introduced the YOURLS server-side proxy. The idea was to allow using the YOURLs URL shortener without running the YOURLs instance without authentication and/or…

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exposing the authentication token to the public, allowing anyone to shorten any URL. With the proxy mechanism, anyone can shorten any URL pointing to the configured PrivateBin instance. The vulnerability allowed other URLs to be shortened, as long as they contain the PrivateBin instance, defeating the limit imposed by the proxy. This vulnerability is fixed in 1.7.4.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-0869Shared CWE-305
CVE-2023-36497Shared CWE-305
CVE-2024-42513Shared CWE-305
CVE-2026-44232Shared CWE-791
CVE-2025-52996Shared CWE-305
CVE-2025-46750Shared CWE-305
CVE-2025-4994Shared CWE-305
CVE-2025-30428Shared CWE-305
CVE-2025-47776Shared CWE-305
CVE-2025-58382Shared CWE-305

Affected Assets

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.4.3
  • V7.2.4

Mitigating Controls (NIST 800-53 r5) AI

Requires unique identification and authentication of users, structurally blocking bypass of the mechanism.

Requires unique identification and authentication of non-organizational users, blocking bypass paths.

Input validation directly requires complete filtering of special elements on received data before further processing or forwarding.

Enforces approved authorizations so a bypass weakness cannot be exploited to reach resources.

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.PS-06 full match
prevents

Secure development practices throughout the SDLC prevent the primary weaknesses that enable authentication bypass.

PR.AA-03 mostly match
prevents

Strong authentication mechanisms and policy enforcement directly reduce bypass opportunities arising from implementation flaws.

ID.RA-01 partial match
prevents

Identifying and recording vulnerabilities catches the primary weaknesses that allow authentication bypass.

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.

finds

Security testing can detect authentication bypass conditions before deployment.

prevents

Secure development lifecycle reduces likelihood of introducing bypass flaws during implementation.

prevents

Application security requirements explicitly call for input validation and sanitization that directly mitigates incomplete special-element filtering.

prevents

Secure system architecture and engineering principles require defensive design patterns that prevent unfiltered data from reaching downstream components.

prevents

Secure coding practices help prevent the primary weakness that enables authentication bypass.

mitigates

Information access restriction complements authentication by limiting what can be reached even if bypass occurs.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Ubuntu 22.04 (1 rule)
  • V-260470 Ubuntu 22.04 LTS, when booted, must require authentication upon booting into single-user and maintenance modes. prevents CWE-305
Ubuntu 24.04 (1 rule)
  • V-270675 Ubuntu 24.04 LTS when booted must require authentication upon booting into single-user and maintenance modes. prevents CWE-305

References