NLTK: Pl196xCorpusReader has quadratic ReDoS on malformed TEI blocks

Summary Pl196xCorpusReader still parses whole TEI blocks with multiple lazy regexes over attacker-controlled text. A malformed file with many opening tags and no matching closing tags forces repeated rescans and produces quadratic CPU growth in public reader APIs. Details - Vulnerability type:...

SUSE CVE-2026-81725

NLTK before 3.10.3 contains a regular expression denial of service vulnerability in Pl196xCorpusReader that allows attackers to cause quadratic CPU consumption by supplying malformed TEI blocks with many unmatched opening tags. Attackers can exploit lazy regex patterns in the readblock method...

PYSEC-2026-3752

NLTK before 3.10.3 contains a regular expression denial of service vulnerability in Pl196xCorpusReader that allows attackers to cause quadratic CPU consumption by supplying malformed TEI blocks with many unmatched opening tags. Attackers can exploit lazy regex patterns in the readblock method...

CVE-2026-81725

NLTK before 3.10.3 contains a regular expression denial of service vulnerability in Pl196xCorpusReader that allows attackers to cause quadratic CPU consumption by supplying malformed TEI blocks with many unmatched opening tags. Attackers can exploit lazy regex patterns in the readblock method...

CVE-2026-81725 NLTK before 3.10.3 Regular Expression Denial of Service via Pl196xCorpusReader

NLTK before 3.10.3 contains a regular expression denial of service vulnerability in Pl196xCorpusReader that allows attackers to cause quadratic CPU consumption by supplying malformed TEI blocks with many unmatched opening tags. Attackers can exploit lazy regex patterns in the readblock method...

Linux Distros Unpatched Vulnerability : CVE-2026-81725

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - NLTK before 3.10.3 contains a regular expression denial of service vulnerability in Pl196xCorpusReader that allows attackers to cause quadratic CPU consumption ...

PT-2026-82620

Name of the Vulnerable Software and Affected Versions NLTK versions prior to 3.10.3 Description A regular expression denial of service exists in Pl196xCorpusReader. An attacker can cause quadratic CPU consumption by providing malformed TEI Text Encoding Initiative blocks containing numerous...