Security Bulletin: Multiple Vulnerabilities in IBM Concert Operate / IBM Cloud Pak for AIOps

Summary Multiple vulnerabilities were addressed in IBM Concert Operate version 5.2.0 Vulnerability Details CVEID:CVE-2026-24281 DESCRIPTION: Hostname verification in Apache ZooKeeper ZKTrustManager falls back to reverse DNS PTR when IP SAN validation fails, allowing attackers who control or spoof...

SUSE 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...

GHSA-WW6M-CW3F-Q94G NLTK: Quadratic-time DoS in PorterStemmer via long runs of 'y'

nltk.stem.PorterStemmer.stem -- a ubiquitous public API applied to arbitrary, often untrusted, tokens -- runs in On^2 time on a token containing a long run of the letter 'y', letting a single 20-50 KB token pin a CPU core CWE-407. Root cause isconsonantword, i was made iterative commit for 3633,...

EUVD-2026-67072

NLTK: Quadratic-time DoS in PorterStemmer via long runs of 'y'...

NLTK: Quadratic-time DoS in PorterStemmer via long runs of 'y'

nltk.stem.PorterStemmer.stem -- a ubiquitous public API applied to arbitrary, often untrusted, tokens -- runs in On^2 time on a token containing a long run of the letter 'y', letting a single 20-50 KB token pin a CPU core CWE-407. Root cause isconsonantword, i was made iterative commit for 3633,...

CVE-2026-81722

A flaw was found in the nltk PorterStemmer component. A remote attacker could exploit this vulnerability by providing a specially crafted, untrusted token. The inefficient algorithmic complexity in the stemming process, specifically within the isconsonant and measure helper functions, causes...

Duplicate Advisory: Quadratic-time DoS in PorterStemmer via long runs of 'y'

Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-ww6m-cw3f-q94g. This link is maintained to preserve external references. Original Description nltk PorterStemmer in versions = 3.10.2 fixed in 3.10.3 contains an inefficient-algorithmic-complexity denial of...

GHSA-8X48-8G7J-RQXP Duplicate Advisory: Quadratic-time DoS in PorterStemmer via long runs of 'y'

Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-ww6m-cw3f-q94g. This link is maintained to preserve external references. Original Description nltk PorterStemmer in versions = 3.10.2 fixed in 3.10.3 contains an inefficient-algorithmic-complexity denial of...

PYSEC-2026-3738

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...

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...

PYSEC-2026-3738

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-2026-81722

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...

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...

CVE-2026-81722 nltk PorterStemmer before 3.10.3 Quadratic-time DoS

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...

CVE-2026-81722

nltk PorterStemmer in versions ≤ 3.10.2 is vulnerable to an inefficient-algorithmic-complexity denial of service in PorterStemmer.stem(). The root cause is that the _is_consonant() helper walks backward over the entire run of trailing 'y' characters on every call, and _measure() invokes it for ea...

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...

CVE-2026-81722 nltk PorterStemmer before 3.10.3 Quadratic-time DoS

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...

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...

CVE-2026-81722 nltk PorterStemmer before 3.10.3 Quadratic-time DoS

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...

Inefficient Algorithmic Complexity

Overview nltk is a Natural Language Toolkit NLTK is a Python package for natural language processing. Affected versions of this package are vulnerable to Inefficient Algorithmic Complexity via the PorterStemmer.stem path in nltk/stem/porter.py. An attacker can pin a CPU core by supplying a single...