CVE-2023-27533
Splunk Universal Forwarder 8.2.0 – 8.2.12
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-27533 is a high-severity Special Element Injection (CWE-75) vulnerability in Splunk Universal Forwarder. Its CVSS base score is 8.8 (High).
Operationally, ranked in the top 20% 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-2023-31288
Vulnerability Data
A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an…
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attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an application allows user input, thereby enabling attackers to execute arbitrary code on the system.
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
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.
Developer assessments and testing (including injection-focused techniques) identify improper neutralization of special elements, and the verifiable flaw remediation corrects them pre-deployment.
Identifies indicators of injection attacks (command, SQL, LDAP, etc.) via anomaly and attack monitoring.
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.
Logging can record injection attempts for detection but does not prevent the weakness.
Monitoring activities can identify active injection attacks after they occur.
A.8.25 mandates secure SDLC practices including secure coding guidelines, security requirements, checkpoints, testing (scans/penetration), and developer training that reach special-element injection in the development phase, but leaves a bounded remainder (e.g. outsourced development without full assurance per 8.30, incomplete enforcement of guidelines across all languages/projects, or post-development injection vectors).
Application security requirements explicitly call for controls against injection flaws including special-element handling.
A.8.27 mandates security engineering principles including data validation/sanitization, distrust external input, security by design, and design reviews against attack patterns; this directly stops special-element injection from being exploitable in most cases, with a bounded remainder in incomplete implementation or novel attack patterns.
Secure coding standards require rigorous input sanitization, directly eliminating CWE-75.
Hardening callouts derived
DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.
- No fine-grained STIG row for CWE-75, a class-level weakness, and none of its children carries one either.
- No fine-grained STIG row for CWE-74, a class-level weakness, and none of its children carries one either.