FKIE_CVE-2025-6435
Vulnerability from fkie_nvd - Published: 2025-06-24 13:15 - Updated: 2026-06-17 10:01
Severity
Summary
If a user saved a response from the Network tab in Devtools using the Save As context menu option, that file may not have been saved with the `.download` file extension. This could have led to the user inadvertently running a malicious executable. This vulnerability was fixed in Firefox 140 and Thunderbird 140.
References
| URL | Tags | ||
|---|---|---|---|
| security@mozilla.org | https://bugzilla.mozilla.org/show_bug.cgi?id=1950056 | Permissions Required | |
| security@mozilla.org | https://bugzilla.mozilla.org/show_bug.cgi?id=1961777 | Permissions Required | |
| security@mozilla.org | https://www.mozilla.org/security/advisories/mfsa2025-51/ | Vendor Advisory | |
| security@mozilla.org | https://www.mozilla.org/security/advisories/mfsa2025-54/ | Vendor Advisory |
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| mozilla | firefox | * | |
| mozilla | thunderbird | * |
{
"affected": [
{
"affectedData": [
{
"product": "Firefox",
"vendor": "Mozilla",
"versions": [
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "140",
"versionType": "rpm"
}
]
},
{
"product": "Thunderbird",
"vendor": "Mozilla",
"versions": [
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "140",
"versionType": "rpm"
}
]
}
],
"source": "security@mozilla.org"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*",
"matchCriteriaId": "6BD96DBF-567C-4E36-844D-B25A4E22CE40",
"versionEndExcluding": "140.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*",
"matchCriteriaId": "EE6112E1-F482-4916-BA5E-68868793540F",
"versionEndExcluding": "140.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "If a user saved a response from the Network tab in Devtools using the Save As context menu option, that file may not have been saved with the `.download` file extension. This could have led to the user inadvertently running a malicious executable. This vulnerability was fixed in Firefox 140 and Thunderbird 140."
},
{
"lang": "es",
"value": "Si un usuario guard\u00f3 una respuesta desde la pesta\u00f1a Red en DevTools mediante la opci\u00f3n Guardar como del men\u00fa contextual, es posible que el archivo no se haya guardado con la extensi\u00f3n `.download`. Esto podr\u00eda haber provocado que el usuario ejecutara accidentalmente un archivo malicioso. Esta vulnerabilidad afecta a Firefox anterior a la versi\u00f3n 140."
}
],
"id": "CVE-2025-6435",
"lastModified": "2026-06-17T10:01:53.377",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.1,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.2,
"impactScore": 5.9,
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2025-6435",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2025-06-24T13:37:09.229042Z",
"version": "2.0.3"
}
}
]
},
"published": "2025-06-24T13:15:24.560",
"references": [
{
"source": "security@mozilla.org",
"tags": [
"Permissions Required"
],
"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1950056"
},
{
"source": "security@mozilla.org",
"tags": [
"Permissions Required"
],
"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1961777"
},
{
"source": "security@mozilla.org",
"tags": [
"Vendor Advisory"
],
"url": "https://www.mozilla.org/security/advisories/mfsa2025-51/"
},
{
"source": "security@mozilla.org",
"tags": [
"Vendor Advisory"
],
"url": "https://www.mozilla.org/security/advisories/mfsa2025-54/"
}
],
"sourceIdentifier": "security@mozilla.org",
"vulnStatus": "Modified",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-434"
}
],
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
]
}
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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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