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.

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

  - 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.
    (CVE-2026-81722)

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

  - 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.
    (CVE-2026-81722)

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

ID	Name	Product	Family	Type	Severity
465545	Echo: nltk: security update to 3.10.3	Tenable Cloud Security	Echo Local Security Checks	Local	high
465545	Echo: nltk: security update to 3.10.3	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
341148	Linux Distros Unpatched Vulnerability : CVE-2026-81722	Nessus	Misc.	Local	high

Detections

Analytics

CVE-2026-81722

high

Tenable Plugins

high

high

high