{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "4.0.0"
                  },
                  {
                    "fixed": "4.3.2"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              },
              {
                "range": [
                  {
                    "introduced": "4.4.0"
                  },
                  {
                    "fixed": "4.5.0"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              },
              {
                "range": [
                  {
                    "fixed": "4e0a5f38b14dba5891fb558c49a526f9f6a3cc29"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              }
            ]
          },
          "events": [
            {
              "introduced": "8469084dfae85f854555f0607f2c838dad097235"
            },
            {
              "fixed": "28af05ca658cbacf745fd5b099566311c58ccb1d"
            },
            {
              "introduced": "684c9e8f32e4373a21098559f748f06915f950c9"
            },
            {
              "fixed": "41d10b59730406bbab4ca9f1fbbe9e96aafb4966"
            },
            {
              "fixed": "4e0a5f38b14dba5891fb558c49a526f9f6a3cc29"
            }
          ],
          "repo": "https://github.com/zephyrproject-rtos/zephyr",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-8jrg-wx88-g75j"
  ],
  "database_specific": {
    "cna_assigner": "zephyr",
    "cwe_ids": [
      "CWE-787"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82391.json"
  },
  "details": "The HTTP/2 front-end of the Zephyr HTTP server aliased connection receive state as a scratch output. In subsys/net/lib/http/http_server_http2.c, handle_http2_static_fs_resource() passed \u0026client-\u003edata_len as the file_size out-parameter of http_server_find_file(). client-\u003edata_len is the count of unprocessed bytes remaining in the fixed-size per-connection receive buffer client-\u003ebuffer[CONFIG_HTTP_SERVER_CLIENT_BUFFER_SIZE] (256 bytes by default), an invariant every frame handler and the socket receive path rely on. Serving any static file therefore replaced that bounded value with the file's on-disk size, and nothing resets it afterwards.\n\nThe defect is reached by an unauthenticated HTTP/2 GET for any file under the web root, in applications that register a static-filesystem resource (HTTP_RESOURCE_TYPE_STATIC_FS) with CONFIG_FILE_SYSTEM=y; CONFIG_HTTP_SERVER_VERSION_2 is enabled by default and no TLS or credentials are required on this path. Once client-\u003edata_len exceeds the buffer size, the frame dispatch loop in subsys/net/lib/http/http_server_core.c keeps parsing past the end of the received data, and the peer controls the bytes at client-\u003ecursor, so it can choose which fabricated frame the state machine consumes next by appending bytes after its request.\n\nThe inflated length defeats the only guards on the buffer. parse_http_frame_header() and the per-frame handlers read and skip up to a 24-bit frame length beyond the buffer (out-of-bounds read); the compaction memmove(client-\u003ebuffer, client-\u003ecursor, client-\u003edata_len) at the end of request handling copies the file-size number of bytes into the 256-byte buffer, overflowing the rest of struct http_client_ctx — including the current_detail/current_stream pointers, the parser_settings function-pointer table and the inactivity_timer work handler — and the adjacent client contexts in static memory; and the subsequent zsock_recv(client-\u003efd, client-\u003ebuffer + client-\u003edata_len, sizeof(client-\u003ebuffer) - client-\u003edata_len, 0) underflows its size argument, writing attacker-supplied data of attacker-chosen length out of bounds.\n\nThe impact is remote memory corruption in the server's single address space: at minimum a crash or hang of the device, and plausibly control-data overwrite leading to code execution. The HTTP/1 and HTTP/3 static-filesystem handlers already used a local variable and are unaffected; the fix makes the HTTP/2 handler use a local size_t file_size as well.",
  "id": "CVE-2026-82391",
  "modified": "2026-11-12T02:30:27.703259410Z",
  "published": "2026-11-10T22:07:39.047Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82391.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-8jrg-wx88-g75j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-82391"
    },
    {
      "type": "FIX",
      "url": "https://github.com/zephyrproject-rtos/zephyr/commit/4e0a5f38b14dba5891fb558c49a526f9f6a3cc29"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/zephyrproject-rtos/zephyr"
    }
  ],
  "schema_version": "1.9.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Out-of-bounds write in Zephyr HTTP/2 server static-filesystem handler via corrupted receive-buffer length"
}