CVE-2026-57073 in HTML::Bare
Summary
by MITRE • 07/16/2026
HTML::Bare versions through 0.04 for Perl have an unbounded character lookahead.
The parserc_parse function attempts to check for multicharacter strings such as "<![CDATA" or element terminators such as ">" without checking that the offsets are within the buffer.
Truncated strings such as "<a/" can trigger an out-of-bounds read.
Note that the latest version available on CPAN is version 0.02. Newer versions are available on the git repository.
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Analysis
by VulDB Data Team • 07/16/2026
The HTML::Bare Perl module through version 0.04 contains a critical buffer overflow vulnerability in its parsing functionality that stems from inadequate bounds checking during string validation operations. This vulnerability manifests in the parserc_parse function which processes HTML content without proper verification of memory boundaries when examining multicharacter sequences such as CDATA declarations or element terminators. The flaw specifically occurs when the parser attempts to validate strings like "<![CDATA" or ">" characters without ensuring that the character offsets remain within the confines of the allocated buffer space, creating a potential avenue for memory corruption and arbitrary code execution.
The technical implementation of this vulnerability relies on improper input validation where the parser function does not perform bounds checking before accessing character positions in the input stream. When processing truncated HTML strings such as "<a/", the parser attempts to access memory locations beyond the actual buffer boundaries, resulting in out-of-bounds read conditions that can lead to information disclosure or system instability. This behavior aligns with CWE-129, which describes improper validation of array indices, and represents a classic example of unchecked buffer access that violates fundamental security principles for input sanitization.
The operational impact of this vulnerability extends beyond simple memory corruption as it creates potential attack vectors for remote code execution when the affected module processes untrusted HTML content. Attackers could craft malicious HTML fragments that trigger the out-of-bounds read condition, potentially leading to denial of service scenarios or more severe exploitation depending on the system configuration and memory layout. This vulnerability particularly affects applications that utilize HTML::Bare for parsing user-supplied content without additional input validation layers, making it a significant concern for web applications and content processing systems.
From a threat modeling perspective, this vulnerability maps to ATT&CK technique T1203 by enabling adversaries to manipulate application behavior through input injection, while also representing a potential path for privilege escalation if the vulnerable application operates with elevated permissions. The attack surface is broad since HTML::Bare is commonly used in web applications, content management systems, and any Perl-based application that requires HTML parsing capabilities. Security practitioners should be aware that this vulnerability exists in versions prior to 0.02 on CPAN, though newer versions may be available through the git repository, indicating that proper patch management and version control are essential for maintaining system security.
The recommended mitigation strategy involves immediate upgrading to the latest available version from the git repository as the official CPAN release appears to be outdated. Organizations should also implement input validation layers that sanitize HTML content before processing, employ memory protection mechanisms such as stack canaries, and consider deploying runtime application self-protection solutions to detect and prevent exploitation attempts. Additionally, regular security audits of Perl module dependencies should be conducted to identify similar vulnerabilities in other third-party libraries that may pose comparable risks to system integrity and data confidentiality.