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

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-16 · updated 2026-10-20
Weakness: CWE-1286

Description

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. 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 products

Text-CSV_XS: before 1.65 — fixed in 1.65

How to fix

Upgrade to a fixed version: Text-CSV_XS 1.65. Check the vendor advisory for mitigations.

References

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