What is the CVSS score of CVE-2023-27539?

CVE-2023-27539 has a CVSS 3.1 base score of 5.3 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L. EPSS exploitation probability: 0.3%.

How to fix or mitigate CVE-2023-27539?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Vendor patch is available.

Rack CVE-2023-27539

MEDIUM

2025-01-09 support@hackerone.com

Denial Of Service Debian Red Hat Debian Linux Rack Suse

5.3

CVSS 3.1 · NVD

View

Vulnerability Assessment

Impact	CVSS score of 5.3 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. EPSS exploitation probability: 0.33%.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

There is a denial of service vulnerability in the header parsing component of Rack. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

Earlier versions of this analysis (1)

v1 Mar 28, 2026 - 18:02 CVSS 5.3

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affected Packages

rubygems rack fix: 2.2.6.4, 3.0.6.1

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in rubygems

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

There is a denial of service vulnerability in the header parsing component of Rack. Affected products include: Rack, Debian Debian Linux.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.3 MEDIUM

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

SUSE MEDIUM

Red Hat 5.3 MEDIUM

Primary rating from NVD.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Lifecycle Timeline

Patch released

Mar 28, 2026 - 18:02 nvd

Patch available

CVE Published

Jan 09, 2025 - 01:15 nvd

MEDIUM 5.3

DescriptionCVE.org

There is a denial of service vulnerability in the header parsing component of Rack.

Executive ViewAI

Why It Matters

Organizations using There should be aware of moderate risk from CVE-2023-27539 rated CVSS 5.3. Exploitation could compromise the security of affected deployments. A patch is available and should be applied during regular vulnerability management.

Business Impact: Low

Compensating Controls

Apply vendor patch. If patching is delayed: restrict network access and enable monitoring.

Threat Intelligence Overview

EPSS Score

0.3%

Top 44% exploitable

Data Quality

5 sources

Confidence: Medium

NVD

CVE.org

EPSS Vendor

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC No

EPSS 0.3%

Patch available Yes

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

Low

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +26

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Denial of Service MEDIUM

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)CVE.org

cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*

cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

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Vendor StatusVendor

SUSE

Severity: Medium

Product	Status
Image SLES15-SP3-SAP-Azure-LI-BYOS-Production Image SLES15-SP3-SAP-Azure-VLI-BYOS-Production Image SLES15-SP3-SAP-BYOS-Azure Image SLES15-SP3-SAP-BYOS-EC2-HVM Image SLES15-SP3-SAP-BYOS-GCE Image SLES15-SP4-SAP-Azure-LI-BYOS Image SLES15-SP4-SAP-Azure-LI-BYOS-Production Image SLES15-SP4-SAP-Azure-VLI-BYOS Image SLES15-SP4-SAP-Azure-VLI-BYOS-Production Image SLES15-SP4-SAP-BYOS Image SLES15-SP4-SAP-BYOS-Azure Image SLES15-SP4-SAP-BYOS-EC2 Image SLES15-SP4-SAP-BYOS-GCE Image SLES15-SP4-SAP-Hardened Image SLES15-SP4-SAP-Hardened-Azure Image SLES15-SP4-SAP-Hardened-BYOS Image SLES15-SP4-SAP-Hardened-BYOS-Azure Image SLES15-SP4-SAP-Hardened-BYOS-EC2 Image SLES15-SP4-SAP-Hardened-BYOS-GCE Image SLES15-SP4-SAP-Hardened-EC2 Image SLES15-SP4-SAP-Hardened-GCE Image SLES15-SP5-SAP-Azure-3P Image SLES15-SP5-SAP-Azure-LI-BYOS Image SLES15-SP5-SAP-Azure-LI-BYOS-Production Image SLES15-SP5-SAP-Azure-VLI-BYOS Image SLES15-SP5-SAP-Azure-VLI-BYOS-Production Image SLES15-SP5-SAP-BYOS-Azure Image SLES15-SP5-SAP-BYOS-EC2 Image SLES15-SP5-SAP-BYOS-GCE Image SLES15-SP5-SAP-Hardened-Azure Image SLES15-SP5-SAP-Hardened-BYOS-Azure Image SLES15-SP5-SAP-Hardened-BYOS-EC2 Image SLES15-SP5-SAP-Hardened-BYOS-GCE Image SLES15-SP5-SAP-Hardened-EC2 Image SLES15-SP5-SAP-Hardened-GCE Image SLES15-SP6-SAP-Azure-3P Image SLES15-SP6-SAP-Azure-LI-BYOS Image SLES15-SP6-SAP-Azure-LI-BYOS-Production Image SLES15-SP6-SAP-Azure-VLI-BYOS Image SLES15-SP6-SAP-Azure-VLI-BYOS-Production Image SLES15-SP6-SAP-BYOS Image SLES15-SP6-SAP-BYOS-Azure Image SLES15-SP6-SAP-BYOS-EC2 Image SLES15-SP6-SAP-BYOS-GCE Image SLES15-SP6-SAP-Hardened Image SLES15-SP6-SAP-Hardened-Azure Image SLES15-SP6-SAP-Hardened-BYOS Image SLES15-SP6-SAP-Hardened-BYOS-Azure Image SLES15-SP6-SAP-Hardened-BYOS-EC2 Image SLES15-SP6-SAP-Hardened-BYOS-GCE Image SLES15-SP6-SAP-Hardened-EC2 Image SLES15-SP6-SAP-Hardened-GCE Image SLES15-SP7-SAP-Azure Image SLES15-SP7-SAP-Azure-3P Image SLES15-SP7-SAP-Azure-LI-BYOS-Production Image SLES15-SP7-SAP-Azure-VLI-BYOS-Production Image SLES15-SP7-SAP-BYOS-Azure Image SLES15-SP7-SAP-BYOS-EC2 Image SLES15-SP7-SAP-BYOS-GCE Image SLES15-SP7-SAP-EC2 Image SLES15-SP7-SAP-GCE Image SLES15-SP7-SAP-GCE-3P Image SLES15-SP7-SAP-Hardened-Azure Image SLES15-SP7-SAP-Hardened-BYOS-Azure Image SLES15-SP7-SAP-Hardened-BYOS-EC2 Image SLES15-SP7-SAP-Hardened-BYOS-GCE Image SLES15-SP7-SAP-Hardened-GCE	Affected
SUSE Liberty Linux 8	Fixed
SUSE Liberty Linux 9	Fixed
SUSE Linux Enterprise High Availability Extension 15 SP1	Fixed
SUSE Linux Enterprise High Availability Extension 15 SP2	Fixed

References

Advisories & patches

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