Security Vulnerabilities
NLTK before 3.10.3 contains an uncontrolled recursion vulnerability in nltk.featstruct.FeatStructReader that allows unauthenticated attackers to cause a denial of service by supplying deeply nested feature-structure input. Attackers can craft trivial payloads with nested brackets that exceed Python's recursion limit and raise an unhandled RecursionError, crashing applications that parse user-supplied feature structures or feature grammars.
CVSS Score
6.9
EPSS Score
0.003
Published
2026-08-27
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, PerceptronTagger, and maxent parameter APIs when pathsec is enabled.
CVSS Score
8.3
EPSS Score
0.003
Published
2026-08-27
NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incr_download methods that allows attackers to overwrite files outside the install root through pre-existing hardlinks. Attackers with write access to a shared downloader directory can create hardlinks pointing to outside-root files that are then overwritten during normal package extraction, mutating files outside the intended install tree.
CVSS Score
6.9
EPSS Score
0.001
Published
2026-08-27
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 read_block method through public APIs like words() and tagged_words() to force repeated rescans and achieve near-quadratic runtime growth.
CVSS Score
6.3
EPSS Score
0.002
Published
2026-08-27
nltk PorterStemmer in versions <= 3.10.2 (fixed in 3.10.3) contains an inefficient-algorithmic-complexity denial of service in PorterStemmer.stem(). The _is_consonant() helper walks backward over the entire run of trailing 'y' characters on every call, and _measure() invokes it for each stem position, causing O(n^2) behavior. A single ~20-50 KB untrusted token consisting of a long run of the letter 'y' followed by a matching suffix (e.g., 'ness') can pin a CPU core for seconds to minutes, causing availability impact.
CVSS Score
8.7
EPSS Score
0.003
Published
2026-08-27
openssl-encrypt before 1.4.9 fails to redact the file password in its --debug argv dump when the password is supplied via bundled short-option spellings (e.g. -apHunter2) or abbreviated long-option spellings (e.g. --passw). The sanitizer only recognized exact option names, --option=value forms, and tokens starting with -p, so these spellings bypass the redaction chokepoint and the cleartext password is written to stderr. Anyone with access to that output (terminal scrollback, merged 2>&1 output, CI job logs, or the GUI's persistent debug log) can recover the password.
CVSS Score
8.7
EPSS Score
0.003
Published
2026-08-27
openssl_encrypt before 1.4.9 fails to prevent namespace collisions between own identities and contacts in IdentityStore, allowing attackers to create shadowed contact entries invisible until the corresponding own identity is deleted. When the own identity is deleted, the shadowed contact becomes visible and resolves to the attacker's keys, enabling silent key substitution for encrypted files.
CVSS Score
9.3
EPSS Score
0.001
Published
2026-08-27
openssl_encrypt versions before 1.4.9 contain a shell injection vulnerability in the info command's reconstructed CLI block that interpolates untrusted metadata fields without quoting. Attackers can craft metadata values like pepper_name containing shell commands that execute when users copy the printed CLI block into a shell.
CVSS Score
9.3
EPSS Score
0.003
Published
2026-08-27
openssl_encrypt versions before 1.4.9 contain a signature verification vulnerability in gpg_runner.verify_detached that accepts revoked and expired keys by only checking VALIDSIG status without inspecting REVKEYSIG, EXPKEYSIG, or gpg exit codes. Attackers holding compromised-then-revoked signing keys or expired project keys can bypass signature verification to execute malicious plugins in the host process.
CVSS Score
9.3
EPSS Score
0.003
Published
2026-08-27
openssl_encrypt versions before 1.4.9 use a denylist to identify trusted built-in plugins, allowing unsigned plugins in top-level plugins/ directories and unknown subdirectories to bypass signature verification. Attackers can place malicious unsigned plugins following documented installation paths to achieve arbitrary code execution in the CLI process with access to passwords and cryptographic keys.
CVSS Score
9.3
EPSS Score
0.003
Published
2026-08-27