CVE-2026-4671 (GCVE-0-2026-4671)
Vulnerability from cvelistv5 – Published: 2026-08-23 13:34 – Updated: 2026-08-23 13:34
VLAI
EPSS
VEX
Title
justhtml before 1.18.0 Denial of Service via CSS Selector
Summary
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.
Severity
CWE
- CWE-400 - Uncontrolled Resource Consumption
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/EmilStenstrom/justhtml/securit… | vendor-advisory |
| https://www.vulncheck.com/advisories/justhtml-bef… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| EmilStenstrom | justhtml |
Affected:
0 , < 1.18.0
(semver)
Unaffected: 1.18.0 (semver) |
guessed |
Date Public
2026-05-04 00:00
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}
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"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
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"problemTypes": [
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"descriptions": [
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"description": "Uncontrolled Resource Consumption",
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"url": "https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-r8cj-3554-33mr"
},
{
"name": "VulnCheck Advisory: justhtml before 1.18.0 Denial of Service via CSS Selector",
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],
"url": "https://www.vulncheck.com/advisories/justhtml-before-denial-of-service-via-css-selector"
}
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"datePublished": "2026-08-23T13:34:08.443Z",
"dateReserved": "2026-03-23T19:00:14.383Z",
"dateUpdated": "2026-08-23T13:34:08.443Z",
"state": "PUBLISHED"
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"date": "2026-08-24",
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"percentile": "0.29929"
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}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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