{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-54741",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-06-15T23:12:41.964Z",
        "datePublished": "2026-08-19T20:13:05.201Z",
        "dateUpdated": "2026-08-20T13:21:16.938Z"
    },
    "containers": {
        "cna": {
            "title": "Lemmy: Blocked users can edit private messages sent before the block",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-862",
                            "lang": "en",
                            "description": "CWE-862: Missing Authorization",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV4_0": {
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "attackRequirements": "NONE",
                        "privilegesRequired": "LOW",
                        "userInteraction": "NONE",
                        "vulnConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "LOW",
                        "vulnAvailabilityImpact": "NONE",
                        "subConfidentialityImpact": "NONE",
                        "subIntegrityImpact": "NONE",
                        "subAvailabilityImpact": "NONE",
                        "baseScore": 5.3,
                        "baseSeverity": "MEDIUM",
                        "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
                        "version": "4.0"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-46g9-847m-qf8r",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-46g9-847m-qf8r"
                },
                {
                    "name": "https://github.com/LemmyNet/lemmy/pull/6472",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/LemmyNet/lemmy/pull/6472"
                },
                {
                    "name": "https://github.com/LemmyNet/lemmy/pull/6476",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/LemmyNet/lemmy/pull/6476"
                },
                {
                    "name": "https://github.com/LemmyNet/lemmy/commit/051b317c9d14b91972bb372c67f319d6900beb93",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/LemmyNet/lemmy/commit/051b317c9d14b91972bb372c67f319d6900beb93"
                },
                {
                    "name": "https://github.com/LemmyNet/lemmy/commit/2d169d630b86b9351e4b1dca451214b741f46150",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/LemmyNet/lemmy/commit/2d169d630b86b9351e4b1dca451214b741f46150"
                },
                {
                    "name": "https://github.com/LemmyNet/lemmy/releases/tag/0.19.19",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/LemmyNet/lemmy/releases/tag/0.19.19"
                },
                {
                    "name": "https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-alpha.18",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-alpha.18"
                }
            ],
            "affected": [
                {
                    "vendor": "LemmyNet",
                    "product": "lemmy",
                    "versions": [
                        {
                            "version": "< 0.19.19",
                            "status": "affected"
                        },
                        {
                            "version": ">= 1.0.0-alpha.0, < 1.0.0-alpha.18",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-08-19T20:13:05.201Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-alpha.18, Lemmy blocks new private messages from a sender after the recipient blocks that sender, but the edit path skips the same block check. create_private_message checks the recipient's block list with PersonActions::read_block before inserting a message, while edit_private_message in crates/api/api_crud/src/private_message/update.rs only checks that the caller is orig_private_message.creator_id. The update then writes new content and returns the modified PrivateMessageView without consulting the recipient's block list, allowing a blocked sender to keep changing an old message that the recipient can still see and providing a post-block harassment path. This issue is fixed in versions 0.19.19 and 1.0.0-alpha.18."
                }
            ],
            "source": {
                "advisory": "GHSA-46g9-847m-qf8r",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "references": [
                    {
                        "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-46g9-847m-qf8r",
                        "tags": [
                            "exploit"
                        ]
                    }
                ],
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-08-20T13:21:08.131078Z",
                                "id": "CVE-2026-54741",
                                "options": [
                                    {
                                        "Exploitation": "poc"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-08-20T13:21:16.938Z"
                }
            }
        ]
    }
}