{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.19.19"
              },
              {
                "introduced": "1.0.0-alpha.0"
              },
              {
                "fixed": "1.0.0-alpha.18"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "introduced": "1edc9f922debc2c5b1aaaf29c495d7d4fe711b94"
            },
            {
              "fixed": "f6e986e7e54d456aa1ffec38f1576c5bb15e0afd"
            },
            {
              "fixed": "0ab1cd744b659d0f5e35b77dbded142bed550487"
            },
            {
              "fixed": "051b317c9d14b91972bb372c67f319d6900beb93"
            },
            {
              "fixed": "2d169d630b86b9351e4b1dca451214b741f46150"
            }
          ],
          "repo": "https://github.com/lemmynet/lemmy",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-46g9-847m-qf8r"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-862"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54741.json"
  },
  "details": "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",
  "modified": "2026-08-22T03:31:21.047708911Z",
  "published": "2026-08-19T20:13:05.201Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/LemmyNet/lemmy/releases/tag/0.19.19"
    },
    {
      "type": "WEB",
      "url": "https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-alpha.18"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54741.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-46g9-847m-qf8r"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-54741"
    },
    {
      "type": "FIX",
      "url": "https://github.com/LemmyNet/lemmy/commit/051b317c9d14b91972bb372c67f319d6900beb93"
    },
    {
      "type": "FIX",
      "url": "https://github.com/LemmyNet/lemmy/commit/2d169d630b86b9351e4b1dca451214b741f46150"
    },
    {
      "type": "FIX",
      "url": "https://github.com/LemmyNet/lemmy/pull/6472"
    },
    {
      "type": "FIX",
      "url": "https://github.com/LemmyNet/lemmy/pull/6476"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Lemmy: Blocked users can edit private messages sent before the block"
}