Mastodon: Removal of integrity-protected JSON entries from signed activities_CVE-2026-48028

{
    "lastseen": "",
    "description": "Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, Mastodon's normalization of incoming activities signed with Linked-Data Signatures does not sufficiently protect the activities from a certain class of spoofing, allowing threat actors to remove JSON entries from valid signed activities from a third-party actor. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.",
    "published": "2026-06-24T19:43:01.469Z",
    "modified": "2026-06-24T19:43:01.469Z",
    "type": "cve",
    "title": "Mastodon: Removal of integrity-protected JSON entries from signed activities",
    "source": "GitHub_M",
    "references": "https://github.com/mastodon/mastodon/security/advisories/GHSA-53m7-2wrh-q839",
    "id": "CVE-2026-48028",
    "bulletinFamily": "",
    "cwe": [
        "CWE-354"
    ],
    "cvelist": null,
    "sourceData": "mastodon mastodon >= 4.5.0-beta.1, < 4.5.10\nmastodon mastodon >= 4.4.0-beta.1, < 4.4.17\nmastodon mastodon < 4.3.23",
    "sourceHref": "",
    "cvss": {
        "score": 6.5,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "mastodon",
    "version": ">= 4.5.0-beta.1, < 4.5.10",
    "vendor": "mastodon",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
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    "ai_score": 0
}