CVE-2026-80206 Vulnerability Analysis & Exploit Details

CVE-2026-80206
Vulnerability Scoring

5.9
/10
Significant Risk

Security assessments indicate that CVE-2026-80206 presents a notable risk, potentially requiring prompt mitigation.

Attack Complexity Details

  • Attack Complexity: High
    Exploits require significant effort and special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-80206 Details

Status: Analyzed

Last updated: 🕗 01 Sep 2026, 20:07 UTC
Originally published on: 🕚 26 Aug 2026, 11:16 UTC

Time between publication and last update: 6 days

CVSS Release: version 3

CVSS3 Source

disclosure@vulncheck.com

CVSS3 Type

Secondary

CVSS3 Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVE-2026-80206 Vulnerability Summary

CVE-2026-80206: NLTK before 3.10.3 contains a regular expression denial of service (ReDoS) vulnerability in the tgrep module. The _tgrep_node_action function compiles user-supplied regular expressions embedded in /regex/ pattern nodes and executes them via re.search against tree node labels without any validation or timeout. An attacker who controls the tgrep pattern (e.g., via tgrep_positions() or tgrep_compile() exposed to external input) can supply a pattern that triggers catastrophic backtracking, causing indefinite CPU saturation that blocks the Python process.

Assessing the Risk of CVE-2026-80206

Access Complexity Graph

The exploitability of CVE-2026-80206 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-80206

CVE-2026-80206 presents a challenge to exploit due to its high attack complexity, but the absence of privilege requirements still makes it a viable target for skilled attackers. A thorough security review is advised.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-80206, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-80206, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2026-80206 has no significant impact on data confidentiality.
  • Integrity: None
    CVE-2026-80206 poses no threat to data integrity.
  • Availability: High
    CVE-2026-80206 can disrupt system operations, potentially causing complete denial of service (DoS).

CVE-2026-80206 References

External References

CWE Common Weakness Enumeration

CWE-1333

CAPEC Common Attack Pattern Enumeration and Classification

  • Regular Expression Exponential Blowup CAPEC-492 An adversary may execute an attack on a program that uses a poor Regular Expression(Regex) implementation by choosing input that results in an extreme situation for the Regex. A typical extreme situation operates at exponential time compared to the input size. This is due to most implementations using a Nondeterministic Finite Automaton(NFA) state machine to be built by the Regex algorithm since NFA allows backtracking and thus more complex regular expressions.

Vulnerable Configurations

  • cpe:2.3:a:nltk:nltk:2.0.1:rc1:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:2.0.1:rc1:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:2.0.1:rc2:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:2.0.1:rc2:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:2.0.1:rc3:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:2.0.1:rc3:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:2.0.1:rc4:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:2.0.1:rc4:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:2.0.3:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:2.0.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:2.0.4:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:2.0.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.0.0:-:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.0.0:-:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.0.0:beta1:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.0.0:beta1:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.0.0:beta2:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.0.0:beta2:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.0.0:alpha1:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.0.0:alpha1:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.0.0:alpha4:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.0.0:alpha4:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.0.1:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.0.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.0.2:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.0.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.0.3:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.0.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.0.4:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.0.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.0.5:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.0.5:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.1:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.2:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.2.1:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.2.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.2.2:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.2.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.2.3:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.2.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.2.4:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.2.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.2.5:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.2.5:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.3:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.4:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.4.1:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.4.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.4.3:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.4.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.4.4:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.4.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.4.5:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.4.5:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.5:-:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.5:-:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.5:beta1:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.5:beta1:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.6:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.6:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.6.1:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.6.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.6.2:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.6.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.6.3:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.6.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.6.4:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.6.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.6.5:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.6.5:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.6.6:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.6.6:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.6.7:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.6.7:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.7:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.7:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.8:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.8:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.8.1:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.8.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.9:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.9:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.9.1:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.9.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.9.2:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.9.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.9.3:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.9.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.9.4:*:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.9.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.9:beta1:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.9:beta1:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.10.0:-:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.10.0:-:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.10.0:rc1:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.10.0:rc1:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.10.0:rc2:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.10.0:rc2:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.10.1:-:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.10.1:-:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.10.1:rc1:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.10.1:rc1:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.10.1:rc2:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.10.1:rc2:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.10.2:-:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.10.2:-:*:*:*:*:*:*
  • cpe:2.3:a:nltk:nltk:3.10.2:rc1:*:*:*:*:*:*
    cpe:2.3:a:nltk:nltk:3.10.2:rc1:*:*:*:*:*:*

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