CVE-2026-81722

nltk PorterStemmer in versions = 3.10.2 fixed in 3.10.3 contains an inefficient-algorithmic-complexity denial of service in PorterStemmer.stem. The isconsonant helper walks backward over the entire run of trailing 'y' characters on every call, and measure invokes it for each stem position, causin...

UBUNTU-CVE-2026-81726

NLTK through 3.10.3 contains a path traversal vulnerability in model-artifact APIs that bypass pathsec enforcement by using raw file operations on caller-controlled paths. Attackers can read or write files outside allowed sandbox roots through TransitionParser, AveragedPerceptron, PerceptronTagge...

CVE-2026-81723

NLTK versions before 3.10.3 contain a quadratic CPU exhaustion vulnerability in XMLCorpusView.readxmlfragment that rescans accumulated XML fragments on every 1 KiB block read. Attackers can provide malformed XML corpus files to cause severe CPU consumption and denial of service through affected...

UBUNTU-CVE-2026-81723

NLTK versions before 3.10.3 contain a quadratic CPU exhaustion vulnerability in XMLCorpusView.readxmlfragment that rescans accumulated XML fragments on every 1 KiB block read. Attackers can provide malformed XML corpus files to cause severe CPU consumption and denial of service through affected...

UBUNTU-CVE-2026-81727

NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incrdownload methods that allows attackers to overwrite files outside the install root through pre-existing hardlinks. Attackers with write access to a shared downloader...

UBUNTU-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...

SUSE CVE-2026-63311

NLTK before 3.10.0 affected versions = 3.9.4 contains a server-side request forgery SSRF vulnerability in the validatenetworkurl function in nltk/pathsec.py. The resolvehostname helper catches OSError and ValueError during socket.getaddrinfo and returns an empty list; when DNS resolution fails, t...

SUSE CVE-2026-65915

NLTK versions before 3.10.0 contain a logic bug in FileSystemPathPointer.open where the sandbox validation check compares a normalized path against itself, making the security check permanently inert. Attackers can pass file:// URLs to nltk.data.load to read arbitrary files accessible to the...

CVE-2026-81727 NLTK before 3.10.3 Hardlink File Overwrite via downloader

NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incrdownload methods that allows attackers to overwrite files outside the install root through pre-existing hardlinks. Attackers with write access to a shared downloader...

CVE-2026-81727

NLTK versions before 3.10.3 are affected by a filesystem containment bypass in the Downloader.download and Downloader.incr_download methods. An attacker with write access to a shared downloader directory can create hardlinks pointing to files outside the install root, which are then overwritten d...

CVE-2026-81727

NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incrdownload methods that allows attackers to overwrite files outside the install root through pre-existing hardlinks. Attackers with write access to a shared downloader...

CVE-2026-81727 NLTK before 3.10.3 Hardlink File Overwrite via downloader

NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incrdownload methods that allows attackers to overwrite files outside the install root through pre-existing hardlinks. Attackers with write access to a shared downloader...

CVE-2026-81727 NLTK before 3.10.3 Hardlink File Overwrite via downloader

NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incrdownload methods that allows attackers to overwrite files outside the install root through pre-existing hardlinks. Attackers with write access to a shared downloader...

CVE-2026-81727

NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incrdownload methods that allows attackers to overwrite files outside the install root through pre-existing hardlinks. Attackers with write access to a shared downloader...

CVE-2026-81725

NLTK before 3.10.3 contains a Regular Expression Denial of Service vulnerability in the Pl196xCorpusReader component. The root cause lies in lazy regex patterns within the read_block method, which can be triggered by supplying malformed TEI blocks containing many unmatched opening tags. Attackers...

CVE-2026-81726 NLTK through 3.10.3 Path Traversal via Model-Artifact APIs

NLTK through 3.10.3 contains a path traversal vulnerability in model-artifact APIs that bypass pathsec enforcement by using raw file operations on caller-controlled paths. Attackers can read or write files outside allowed sandbox roots through TransitionParser, AveragedPerceptron, PerceptronTagge...

CVE-2026-81726

NLTK through 3.10.3 contains a path traversal vulnerability in model-artifact APIs that bypass pathsec enforcement by using raw file operations on caller-controlled paths. Attackers can read or write files outside allowed sandbox roots through TransitionParser, AveragedPerceptron, PerceptronTagge...

CVE-2026-81726

NLTK through 3.10.3 contains a path traversal vulnerability in its model-artifact APIs. The root cause is that TransitionParser, AveragedPerceptron, PerceptronTagger, and maxent parameter APIs bypass pathsec enforcement by performing raw file operations on caller-controlled paths, allowing attack...

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...

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...