nltk: nltk PorterStemmer in versions <= 3.10.2 (fixed in 3.10.3) contains an inefficient-algorithmic-complexity denial of s...
CVE-2026-81722 is fixed in nltk on 1 platform by DEBIAN-CVE-2026-81722 (version 3.10.3-1), released August 28, 2026. It is not reported as exploited. Patch Radar priority: Routine.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| nltk · Debian 14 | 3.10.3-1 | DEBIAN-CVE-2026-81722 | Aug 28, 2026 |
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