External risk intelligence

Text::CSV_XS Perl Module Record Truncation Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-110756

Text::CSV_XS is a software library (module) for Perl used by developers to process data. It is not an internet-facing service, appliance, or application. Vulnerabilities in libraries are typically triggered by local data processing or internal application logic, making public-internet exposure of the vulnerable component itself highly unlikely in standard deployments.

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This advisory concerns a flaw in a Perl software library that handles comma-separated values. The issue can cause data corruption or mishandling when processing specific text encodings, potentially leading to incorrect data interpretation by downstream systems. The main concern is confirming relevance and exposure within your specific technology landscape.

Text processing library has a data integrity issue.
It could impact systems processing text data.
Confirm relevance and exposure across your environment.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by providing specially crafted CSV data to a system using a vulnerable version of Text::CSV_XS. This could occur if the system processes external data, such as user-uploaded files. The flaw lies in how the library handles UTF-8 encoded fields that are followed by invalid UTF-8 bytes, leading to corrupted data parsing.

Entry condition: Malicious CSV data provided.
Trigger point: Processing CSV with specific UTF-8 fields.
Resulting risk: Data corruption and potential disclosure.

Live Threat

Current exploitation, exposure, and threat context

When processing CSV data containing UTF-8 flagged fields followed by invalid UTF-8 bytes, this vulnerability could lead to malformed records. Specifically, the end of a record, including its line ending and closing quote if applicable, may be dropped. This could cause subsequent records to be incorrectly parsed as part of the same field when read by applications.

CSV data integrity.
Processing malformed UTF-8 data.
Incorrect data interpretation.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Text::CSV_XS affects Perl applications processing specific UTF-8 data, impacting data integrity and potentially leading to data injection. Application owners and platform teams should prioritize identifying instances of this library, assessing their exposure to malformed UTF-8 input, and coordinating remediation efforts, which may involve vendor coordination for library updates.

Application owners should own the issue.
Verify data processing with malformed UTF-8.
Plan for library updates or code changes.

Supplementary metadata

CVSS vector

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Frequently asked questions

What is Text::CSV_XS?

Text::CSV_XS is a specialized software library designed for the Perl programming language. Developers integrate this component into their applications to efficiently parse, manipulate, and generate comma-separated values (CSV) files. It serves as a backend tool for processing structured text data, ensuring that records and fields are formatted correctly according to standard CSV specifications during software operations.

What does CVE-2026-110756 mean?

This CVE identifies a data integrity flaw classified under CWE-116, which involves improper encoding or escaping of outputs. Specifically, the library fails to correctly finalize a record when it encounters a mix of valid UTF-8 flagged fields and invalid trailing bytes. This causes the software to silently drop the end of a record, leading to mismatched delimiters and corrupted data structures that can deceive downstream applications.

How is this vulnerability triggered?

An attacker must supply malformed CSV data to a system utilizing the affected library. The bug occurs during the 'print' operation when a UTF-8 flagged field is immediately followed by invalid UTF-8 byte sequences. The vulnerability is not triggered by standard, well-formed CSV files; it specifically requires the input to contain these distinct, problematic encoding patterns that confuse the library's buffer flushing logic.

Is my system at risk according to Halo Surface Signal?

Halo Surface Signal indicates that high-risk exposure is very unlikely. Because Text::CSV_XS is a library rather than a standalone internet-facing service or appliance, it does not have a direct public attack surface. The vulnerability requires the internal application logic to process malicious data, meaning the risk is typically isolated to environments that ingest untrusted CSV files from external sources.

What should I do if I use this library?

First, perform an inventory to identify applications that include Text::CSV_XS in their dependency stack. Once located, prioritize updating to version 1.65 or later, which contains the fix for the record truncation issue. If an immediate update is not feasible, implement strict input validation to sanitize or reject CSV files containing malformed UTF-8 characters before they are passed to the library for processing.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.