External risk intelligence

Text::CSV_XS Record Splitting Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-110757

Text::CSV_XS is a Perl library used by developers within applications to process data. It is a build-time or code-level dependency rather than a standalone network-accessible service, appliance, or gateway. Consequently, it lacks a direct public-facing attack surface in common deployments, as its exposure depends entirely on how a developer implements it within their own application logic.

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 vulnerability in a widely used Perl library for processing text data. The issue allows specially crafted data to be misinterpreted, potentially causing records to be split incorrectly. The main concern is confirming relevance and exposure within your specific application environments.

Data can be misread and split.
Affects how data is processed.
Confirm if this library is used.

Attack Path

How an attacker could exploit the issue

An attacker could leverage this vulnerability by supplying specially crafted data to an application that uses a vulnerable version of the Text::CSV_XS Perl module. If the application processes this data without properly quoting fields that contain numbers with leading or trailing whitespace, the module might misinterpret a numeric field as the end of a record. This misinterpretation can lead to the data being split into unintended rows, potentially allowing an attacker to manipulate or inject data.

Entry condition: Application uses vulnerable module.
Trigger point: Unquoted numeric fields with whitespace.
Resulting risk: Data record splitting and manipulation.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow an attacker to manipulate data processed by applications using Text::CSV_XS. Specifically, when a value is treated as a number, it could be written without quotes, causing a record to end prematurely. This could misrepresent or corrupt data, potentially leading to incorrect processing of subsequent fields as a new, separate record.

Corrupted or misrepresented data records.
Malicious input tricks data parsing.
Application misbehavior, data corruption.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Text::CSV_XS affects applications that parse or generate CSV data and could lead to record splitting if numeric values are not properly quoted. Responsibility likely falls to application development teams or platform teams managing Perl environments, with the first step being to identify all instances of the affected library, assess their exposure via application logic, and confirm business criticality.

Application owners should prioritize investigation.
Verify reachability and criticality of applications.
Plan remediation based on documented risk.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is Text::CSV_XS?

Text::CSV_XS is a high-performance Perl module used by developers to parse and generate CSV files. It is a fundamental library that handles the heavy lifting of converting data structures into properly formatted text or reading comma-separated values into a program. Developers include it as a code-level dependency within their own custom Perl applications, rather than running it as a standalone server or software product.

What does CVE-2026-110757 mean?

This CVE describes a weakness classified as CWE-116, which relates to improper encoding or escaping of output. In this specific case, the library fails to recognize when a value containing a number and hidden whitespace requires protective quotes. Because it mistakenly treats such values as simple numbers, the library writes them unquoted. This allows a newline character buried in the data to be interpreted as an instruction to break the file into a new, separate row.

How is this vulnerability triggered?

An attacker must supply specially crafted input that is processed by an application using the vulnerable module. The bug triggers specifically when the library processes a numeric-flagged string containing a newline, such as '12\n', and chooses not to wrap it in quotes. If the application logic does not manually enforce strict quoting, the library's internal behavior forces an premature record split. Data that does not contain these specific numeric formatting artifacts will not trigger the bug.

Why does Halo Surface Signal categorize this as unlikely?

Halo Surface Signal notes that this is a library, not a public network service. Because it is embedded code, there is no direct path for an attacker to reach it over the internet without going through the specific application logic built by a developer. Its exposure is entirely dependent on whether an application accepts untrusted user input and passes it into a vulnerable version of this Perl module, making general network-based exploitation very difficult.

Do I need to update my servers immediately?

The first step is to identify where Text::CSV_XS is used in your environment, as it is often a hidden dependency. You should work with your development teams to determine if your applications ingest untrusted data that could reach this library. Once you have a map of affected applications, prioritize those that process external data, then coordinate with the developers responsible for those codebases to update to a patched version.

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.