What is the CVSS score of CVE-2026-23836?

CVE-2026-23836 has a CVSS 3.1 base score of 9.9 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. EPSS exploitation probability: 0.1%.

How to fix or mitigate CVE-2026-23836?

Within 24 hours: Identify all affected systems running April 2024 in and apply vendor patches immediately. Vendor patch is available.

Hotcrp CVE-2026-23836

CRITICAL

Improper Input Validation (CWE-20)

2026-01-19 security-advisories@github.com

PHP Hotcrp

9.9

CVSS 3.1 · GitHub Advisory

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Authenticate to HotCRP instance
Exploit

Submit crafted formula input
Execution

Bypass formula sanitization
Impact

Execute arbitrary PHP code on server

Vulnerability Assessment

Weakness	CWE CWE-20 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V2 - Validation and Business Logic Input validation, allowlisting
Exploitation Conditions	HotCRP version 3.1 (April 2024 through pre-3.2 release) with authenticated user access; formula input feature must be accessible to authenticated users with formula creation/editing permissions.
Impact	CVSS 9.9 with patch available. HotCRP is widely used for academic conference peer review. Compromised instances could leak unpublished research, manipulate review scores, or pivot to university networks.
Exploit ScenarioDerived	A malicious paper author submits content with injected code through HotCRP's submission system. When processed by the server, the code executes with HotCRP's privileges, giving the attacker access to all conference submissions and reviewer data.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.

Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

HotCRP conference review software version 3.1 has an inadequate input sanitization flaw (CVSS 9.9) that allows authenticated users to execute arbitrary code on the server through crafted submissions.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:54 CVSS 9.9

Input sanitization bypass in HotCRP enables authenticated RCE on conference review servers.

RemediationAI

Update HotCRP to the patched version. Review submitted content for suspicious payloads.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

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

Technical ContextAI · show details

A regression introduced in April 2024 in HotCRP 3.1 led to inadequately sanitized content (CWE-20), allowing authenticated users to inject and execute code through the conference paper submission or review system.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 9.9 CRITICAL

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

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Patch released

Feb 18, 2026 - 16:01 nvd

Patch available

CVE Published

Jan 19, 2026 - 18:16 nvd

CRITICAL 9.9

DescriptionGitHub Advisory

HotCRP is conference review software. A problem introduced in April 2024 in version 3.1 led to inadequately sanitized code generation for HotCRP formulas which allowed users to trigger the execution of arbitrary PHP code. The problem is patched in release version 3.2.

Executive ViewAI

Why It Matters

Organizations using April 2024 in face critical risk from CVE-2026-23836, a input validation vulnerability rated CVSS 9.9. Successful exploitation could critically impact the confidentiality, integrity, and availability of affected systems. A patch is available and should be applied immediately given the critical severity.

Business Impact: Severe

Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score

0.1%

Top 66% exploitable

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

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 CRITICAL

CISA KEV No

Public POC No

EPSS 0.1%

Patch available Yes

Active threat No

Deciding rule

CRITICAL severity

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.