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CVE-2026-4671

CVE-2026-4671 · justhtml before 1.18.0 Denial of Service via CSS Selector

This page contains facts from public vulnerability sources. Check the original advisory before updating.

justhtml before 1.18.0 contains multiple low-severity denial-of-service issues in CSS selector handling and linkification. Applications that evaluate attacker-controlled selector strings (via query(), matches(), or selector-based transforms), run selector matching over very large untrusted documents, construct DOM trees from untrusted structure, or enable linkification over attacker-controlled text may consume disproportionate CPU or memory. Triggers include oversized selectors, large selector lists, oversized compound selectors, long combinator chains, deeply nested functional pseudo-classes, repeated token/positional matching, cyclic DOM graphs causing non-terminating traversal, and punctuation-heavy or trailing-bracket linkification input. These are availability-only concerns and do not by themselves allow script execution, data disclosure, or sanitizer bypass. Default JustHTML(sanitize=True) usage is not expected to be exposed, since selectors are normally supplied by application code.

CVSS 8.7 · High · EPSS 0.7% · Fix available

Published
Updated

Stack: python

Affected products and versions

  • justhtml

    Versions
    • ≥ 0, < 1.18.0: Affected (semver)
    • 1.18.0: Not affected (semver)

    Update to 1.18.0

  • justhtml PyPI

    Versions
    • 0.1.0
    • 0.10.0
    • 0.11.0
    • 0.12.0
    • 0.13.0
    • 0.13.1
    • 0.14.0
    • 0.15.0
    • 0.16.0
    • 0.17.0
    • 0.18.0
    • 0.19.0
    • 0.2.0
    • 0.20.0
    • 0.21.0
    • 0.22.0
    • 0.23.0
    • 0.24.0
    • 0.25.0
    • 0.26.0
    • 0.27.0
    • 0.28.0
    • 0.29.0
    • 0.3.0
    • 0.30.0
    • 0.31.0
    • 0.32.0
    • 0.33.0
    • 0.34.0
    • 0.35.0
    • 0.36.0
    • 0.37.0
    • 0.38.0
    • 0.39.0
    • 0.4.0
    • 0.40.0
    • 0.5.0
    • 0.5.1
    • 0.5.2
    • 0.6.0
    • 0.7.0
    • 0.8.0
    • 0.9.0
    • 1.0.0
    • 1.1.0
    • 1.10.0
    • 1.11.0
    • 1.12.0
    • 1.13.0
    • 1.14.0
    • 1.15.0
    • 1.16.0
    • 1.17.0
    • 1.2.0
    • 1.3.0
    • 1.4.0
    • 1.5.0
    • 1.6.0
    • 1.7.0
    • 1.8.0
    • 1.9.0
    • 1.9.1
    Affected ranges
    • ECOSYSTEM: < 1.18.0

    Update to 1.18.0

Original sources

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