{"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": "2026-08-19T20:13:05.201Z"}, "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"}}}}

{}

{"affected": [{"affectedData": [{"product": "lemmy", "vendor": "LemmyNet", "versions": [{"status": "affected", "version": "< 0.19.19"}, {"status": "affected", "version": ">= 1.0.0-alpha.0, < 1.0.0-alpha.18"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "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."}], "id": "CVE-2026-54741", "lastModified": "2026-08-19T21:16:58.510", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "LOW", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-08-19T21:16:58.510", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/LemmyNet/lemmy/commit/051b317c9d14b91972bb372c67f319d6900beb93"}, {"source": "security-advisories@github.com", "url": "https://github.com/LemmyNet/lemmy/commit/2d169d630b86b9351e4b1dca451214b741f46150"}, {"source": "security-advisories@github.com", "url": "https://github.com/LemmyNet/lemmy/pull/6472"}, {"source": "security-advisories@github.com", "url": "https://github.com/LemmyNet/lemmy/pull/6476"}, {"source": "security-advisories@github.com", "url": "https://github.com/LemmyNet/lemmy/releases/tag/0.19.19"}, {"source": "security-advisories@github.com", "url": "https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-alpha.18"}, {"source": "security-advisories@github.com", "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-46g9-847m-qf8r"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-862"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,0.19.19)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[1.0.0-alpha.0,1.0.0-alpha.18)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "lemmy", "source": "cna", "vendor": "LemmyNet"}, "product": "lemmy", "vendor": "lemmynet"}], "created": "2026-08-19T22:30:04.955326+00:00", "updated": "2026-08-19T22:30:04.955345+00:00", "vendors": ["lemmynet", "lemmynet$PRODUCT$lemmy"]}