CVE-2023-27536
Auth Bypass in Splunk Universal Forwarder 8.2.0 – 8.2.12
Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:NSummary
CVE-2023-27536 is a medium-severity Authentication Bypass by Primary Weakness (CWE-305) vulnerability in Splunk Universal Forwarder. Its CVSS base score is 5.9 (Medium).
Operationally, ranked in the top 27% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-31291
Vulnerability Data
An authentication bypass vulnerability exists libcurl <8.0.0 in the connection reuse feature which can reuse previously established connections with incorrect user permissions due to a failure to check for changes in the CURLOPT_GSSAPI_DELEGATION option. This vulnerability affects krb5/kerberos/negotiate/GSSAPI transfers and…
more
could potentially result in unauthorized access to sensitive information. The safest option is to not reuse connections if the CURLOPT_GSSAPI_DELEGATION option has been changed.
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 13 hardening rules · 6 OS baselines
V6.4.4V6.5.4V6.5.5V6.5.7
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Detects unauthorized successful logons resulting from improper authentication implementations.
Documented procedures ensure personnel are trained on authentication mechanisms, tangibly lowering the risk of improper authentication being exploited.
Security awareness training instructs users on secure authentication practices and avoiding credential compromise.
Training on authentication mechanisms and best practices decreases the occurrence of improper authentication.
Non-repudiation requires strong authentication mechanisms to irrefutably attribute performed actions to specific individuals or processes.
Session content review can reveal authentication bypasses or failures in session establishment.
Review of authentication-related audit records can detect improper authentication mechanisms or bypasses.
Assessments check authentication mechanisms for correct implementation and effectiveness, reducing successful authentication bypass attempts.
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.
Secure development practices throughout the SDLC prevent the primary weaknesses that enable authentication bypass.
Strong authentication mechanisms and policy enforcement directly reduce bypass opportunities arising from implementation flaws.
PR.AA-04 directly enables verification of identity assertions (mostly preventing CWE-287 in that scope) yet leaves many other authentication failure modes unaddressed (only partial prevention overall).
Identifying and recording vulnerabilities catches the primary weaknesses that allow authentication bypass.
PR.AA-01 supplies and governs credentials/tokens that authentication relies on, removing some weak-credential cases, yet leaves verification logic, missing checks, and protocol flaws untouched.
PR.AA-02 ensures valid enrollment and unique credential binding, which reduces some improper-auth risks at issuance time but leaves runtime claim verification untouched, so each direction only partially addresses the other.
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.
Requiring authentication methods whose strength matches the sensitivity of the data and mandating multi-factor authentication directly blocks attempts to access resources without proving identity.
Verifying user identity before issuing replacement credentials and forcing changes after compromise reduces the likelihood that authentication bypass can be achieved through stolen or weak credentials.
Security testing can detect authentication bypass conditions before deployment.
Mandating segregated approval and oversight for non-human identities reduces the chance that weak or orphaned credentials can be exploited for unauthorized authentication.
Requiring authentication mechanisms and technical parameters for secure connections ensures that network services verify user identity before granting access, preventing exploitation of missing or weak authentication.
Secure development lifecycle reduces likelihood of introducing bypass flaws during implementation.
Hardening callouts derived
Configuration rules from DISA STIG baselines that reduce the attack surface for weaknesses of the type cited by this CVE. Derived transitively via CVE→CWE→STIG over `controls_xwalks` (authoritative rows only).
Windows 10 (1 rule)
- V-220812 Credential Guard must be running on Windows 10 domain-joined systems. via CWE-305