The URLS regular expression in nltk/tokenize/casual.py, compiled into TweetTokenizer.WORD_RE and applied by TweetTokenizer.tokenize, contains a naked-domain branch whose domain-label prefix [a-z0-9]+(?:[.\-][a-z0-9]+)* is unbounded. Input consisting of many alternating label separators can be partitioned in exponentially many ways, and because the branch also requires a trailing top-level domain that such input never supplies, the engine explores those partitions before failing at each offset. A few kilobytes of input therefore consumes seconds to minutes of single-threaded CPU, and the HANG_RE substitution performed before matching does not collapse the pattern. TweetTokenizer is intended for tokenizing untrusted social-media text, so any service that applies it, or the module-level casual_tokenize, to submitted text can be stalled per request without authentication. Version 3.10.1 bounds the label repetition.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - The URLS regular expression in nltk/tokenize/casual.py, compiled into TweetTokenizer.WORD_RE and applied
    by TweetTokenizer.tokenize, contains a naked-domain branch whose domain-label prefix
    [a-z0-9]+(?:[.\-][a-z0-9]+)* is unbounded. Input consisting of many alternating label separators can be
    partitioned in exponentially many ways, and because the branch also requires a trailing top-level domain
    that such input never supplies, the engine explores those partitions before failing at each offset. A few
    kilobytes of input therefore consumes seconds to minutes of single-threaded CPU, and the HANG_RE
    substitution performed before matching does not collapse the pattern. TweetTokenizer is intended for
    tokenizing untrusted social-media text, so any service that applies it, or the module-level
    casual_tokenize, to submitted text can be stalled per request without authentication. Version 3.10.1
    bounds the label repetition. (CVE-2026-72818)

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - The URLS regular expression in nltk/tokenize/casual.py, compiled into TweetTokenizer.WORD_RE and applied     by TweetTokenizer.tokenize, contains a naked-domain branch whose domain-label prefix     [a-z0-9]+(?:[.\-][a-z0-9]+)* is unbounded. Input consisting of many alternating label separators can be     partitioned in exponentially many ways, and because the branch also requires a trailing top-level domain     that such input never supplies, the engine explores those partitions before failing at each offset. A few     kilobytes of input therefore consumes seconds to minutes of single-threaded CPU, and the HANG_RE     substitution performed before matching does not collapse the pattern. TweetTokenizer is intended for     tokenizing untrusted social-media text, so any service that applies it, or the module-level     casual_tokenize, to submitted text can be stalled per request without authentication. Version 3.10.1     bounds the label repetition. (CVE-2026-72818)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
457376	Echo: nltk: security update to 3.10.1	Tenable Cloud Security	Echo Local Security Checks	Local	high
457376	Echo: nltk: security update to 3.10.1	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
338801	Linux Distros Unpatched Vulnerability : CVE-2026-72818	Nessus	Misc.	Local	high

Detections

Analytics

CVE-2026-72818

high

Tenable Plugins

high

high

high