{"id":"CVE-2026-54741","aliases":["EUVD-2026-62843","GHSA-46g9-847m-qf8r"],"status":"published","title":"Lemmy: Blocked users can edit private messages sent before the block","description":"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.","severity":{"version":"4.0","score":5.3,"vector":"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00484,"percentile":0.42138,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-862"],"published":"2026-08-19T20:13:05Z","modified":"2026-10-28T02:31:06Z","products":[{"vendor":"lemmynet","product":"lemmy"}],"references":[{"url":"https://github.com/LemmyNet/lemmy/security/advisories/GHSA-46g9-847m-qf8r","tags":["x_refsource_CONFIRM","exploit","advisory"]},{"url":"https://github.com/LemmyNet/lemmy/pull/6472","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/LemmyNet/lemmy/pull/6476","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/LemmyNet/lemmy/commit/051b317c9d14b91972bb372c67f319d6900beb93","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/LemmyNet/lemmy/commit/2d169d630b86b9351e4b1dca451214b741f46150","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/LemmyNet/lemmy/releases/tag/0.19.19","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-alpha.18","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54741.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54741","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-54741","title":"Lemmy: Blocked users can edit private messages sent before the block","description":"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.","status":"published","published":"2026-08-19T20:13:05.201Z","modified":"2026-08-20T13:21:16.938Z","cvss":[{"version":"4.0","score":5.3,"vector":"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","level":"medium","assessor":"cna"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T13:38:09.774038Z"}],"euvd":[{"id":"EUVD-2026-62843","description":"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.","status":"published","published":"2026-08-19T20:13:05Z","modified":"2026-08-20T13:21:16Z","cvss":[{"version":"4.0","score":5.3,"vector":"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","level":"medium"}],"updated_at":"2026-11-02T18:01:40.451894Z"}],"nvd":[{"id":"CVE-2026-54741","description":"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.","status":"published","published":"2026-08-19T21:16:58.51Z","modified":"2026-09-09T21:15:59.613Z","cvss":[{"version":"4.0","score":5.3,"vector":"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","level":"medium","assessor":"secondary"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T14:12:39.962615Z"}],"osv":[{"id":"CVE-2026-54741","title":"Lemmy: Blocked users can edit private messages sent before the block","description":"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.","status":"published","published":"2026-08-19T20:13:05.201Z","modified":"2026-10-28T02:31:06.719536281Z","cvss":[{"version":"4.0","score":5.3,"vector":"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","level":"medium"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T15:45:10.818486Z"}]}}