CVE-2026-110759: Text::CSV_XS versions before 1.65 for Perl return a 0xFF byte that is not in the input for an empty last field followed by a lone CR in parse
Text::CSVXS versions before 1.65 for Perl return a 0xFF byte that is not in the input for an empty last field followed by a lone CR in parse.
When the input to parse ends in a separator and a lone CR, the parser treats the end of the input as the next character and stores the end-of-file marker in the field as the byte 0xFF. With binary set, parse("a,\r") returns the fields "a" and "\xFF". On UTF-8 flagged input the last field is a UTF-8 flagged string holding that lone byte, which is malformed UTF-8. The same input with a non-empty last field is rejected as an error.
A CRLF file read line by line and chomped ends this way when its last column is empty, so the application receives a byte that is not in its input.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Text::CSV_XSto a version that resolves this vulnerability.Fixed in 1.65
Event History
Frequently Asked Questions
What input and parser settings are required to trigger the incorrect field value?
The input must end with a separator followed by a lone carriage return, such as parse("a,\r"). With binary enabled, the empty final field is returned as a byte 0xFF even though that byte was not present in the input.
Could normal line-by-line processing of CSV files encounter this condition?
Yes. A CRLF file read one line at a time and then chomped can leave a lone CR when the final column is empty, causing the parser to return the unexpected byte in that column.
How does UTF-8 input change the impact?
For UTF-8-flagged input, the final field is returned as a UTF-8-flagged string containing the lone 0xFF byte. This produces malformed UTF-8.
Is the behavior the same when the final field is not empty?
No. With the same trailing lone CR condition but a non-empty final field, parsing is rejected as an error rather than returning the injected 0xFF byte.