CVE-2026-23878: Medium Vulnerability in HotCRP

HotCRP is conference review software that has a medium-severity vulnerability identified as CVE-2026-23878. This vulnerability allows authors with at least one submission on a HotCRP site to exploit the document API and download any associated documents, including PDFs and attachments. The issue was introduced in commit aa20ef288828b04550950cf67c831af8a525f508 and was patched in commit ceacd5f1476458792c44c6a993670f02c984b4a0. Given the potential for unauthorized access to sensitive documents, organizations using HotCRP should take immediate action.

The CVSS score for this vulnerability is 6.5, which highlights its medium severity. The risk to organizations includes the potential exposure of sensitive documents that could lead to confidentiality breaches. Attackers may leverage this vulnerability to access documents that they should not have rights to, leading to significant implications for data privacy and integrity.

Currently, there are no known exploits or public proof of concepts associated with this vulnerability. However, organizations should prioritize patching immediately to mitigate any risks associated with this vulnerability as it may attract the attention of malicious actors.

As this vulnerability affects multiple versions of HotCRP, it is important for organizations to assess their deployments and apply the necessary patches to ensure the security of their systems.

Vulnerability Details

The vulnerability is classified under CWE-201, which pertains to the exposure of sensitive information through the use of an inappropriate API. The attack vector is network-based, with low attack complexity and low privileges required for exploitation. This indicates that an attacker can exploit this vulnerability without requiring significant technical skills.

The following table summarizes the CVSS details for CVE-2026-23878:

Technical Analysis

The root cause of this vulnerability lies in the improper implementation of the document API, which allowed unauthorized access to submitted documents. The attack complexity is low, meaning that attackers can exploit this vulnerability without significant effort. Additionally, only low privileges are required to exploit the vulnerability, which indicates that even users with minimal access can leverage it.

User interaction is not required for this vulnerability to be exploited, which heightens the potential risk. The impact on confidentiality is assessed to be high, as unauthorized users can gain access to sensitive information. However, there is no impact on integrity or availability, as the vulnerability does not affect the ability to modify or access the application itself.

Risk & Impact Analysis

The real-world risk associated with CVE-2026-23878 is significant, especially for organizations that rely on HotCRP for managing conference submissions. The vulnerability can lead to exposure of sensitive documents, potentially compromising the confidentiality of submissions and associated attachments. This could have a detrimental impact on the reputation of the organization and could lead to legal ramifications if sensitive information is disclosed.

Organizations should assess the potential blast radius of this vulnerability. If exploited, the attacker could gain access to a wide range of sensitive documents, affecting multiple submissions and potentially impacting various stakeholders involved in the conference.

Given the CVSS score of 6.5 and the fact that it is not included in the KEV catalog, organizations should address this vulnerability in their priority patch cycle. As there is a medium exploitability factor associated with this vulnerability, timely remediation is crucial to mitigate risks.

Exploitation Status

Affected Versions

The affected version of HotCRP is 3.1. Organizations should ensure they are running the latest version of the software to avoid this vulnerability. If version information is missing, it is advisable to state that all versions prior to the vendor patch are vulnerable.

Mitigation & Remediation

Organizations should prioritize patching immediately by upgrading to the latest version of HotCRP to address CVE-2026-23878. If a patch is not immediately available, organizations should consider implementing workarounds such as restricting access to the document API or reviewing user permissions to limit potential exposure.

In addition, configuration hardening should be considered, including implementing strong access controls and regular audits of document access logs to monitor for unauthorized attempts. Organizations may also want to engage in penetration testing to identify any additional weaknesses.

Detection Guidance

Organizations should monitor logs for any unusual access patterns or attempts to download documents through the API. Behavioral anomalies may indicate potential exploitation of this vulnerability. Network signatures can also be established to detect unauthorized API calls that may indicate an attempt to exploit this vulnerability.

AppSecure Threat Intelligence Insight

CVE-2026-23878 highlights the importance of secure API design in applications, particularly those handling sensitive data. The trend of unauthorized data access via poorly secured APIs continues to be a significant concern for organizations. It is essential for security teams to conduct thorough security assessments and implement best practices when developing and deploying APIs.

To effectively address such vulnerabilities, organizations should create a robust vulnerability management program that includes regular reviews of system architecture and API security. Additionally, staying informed about emerging threats and vulnerabilities through resources such as penetration testing methodology can help organizations proactively address potential risks.

Ultimately, continuous improvement in security practices and awareness is necessary to mitigate the risks associated with vulnerabilities like CVE-2026-23878.