{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-45541: ESF-IDF: Remote Null Pointer Dereference in WebSocket Server","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-45541","status":"final","version":"1","initial_release_date":"2026-06-10T00:25:59.233Z","current_release_date":"2026-06-10T14:40:16.880Z","revision_history":[{"date":"2026-06-10T00:25:59.233Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. In versions 5.2.6, 5.3.5, 5.4.4, 5.5.4, and 6.0, a NULL-pointer dereference exists in the WebSocket subprotocol-negotiation path of the esp_http_server component. While parsing the client-supplied Sec-WebSocket-Protocol request header during the WebSocket handshake, the tokenisation result is dereferenced without a NULL check, so a malformed header value can crash the server before any application-level authentication runs. This issue has been patched in versions 5.2.7, 5.3.6, 5.4.5, 5.5.5, and 6.0.1.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-45541 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-45541"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-45541"},{"category":"external","summary":"https://github.com/espressif/esp-idf/security/advisories/GHSA-3j8v-xgrq-5vg8","url":"https://github.com/espressif/esp-idf/security/advisories/GHSA-3j8v-xgrq-5vg8"},{"category":"external","summary":"https://github.com/espressif/esp-idf/commit/00a2f7fbbbd8fe6d04729022e1d5c9a49435bfe8","url":"https://github.com/espressif/esp-idf/commit/00a2f7fbbbd8fe6d04729022e1d5c9a49435bfe8"},{"category":"external","summary":"https://github.com/espressif/esp-idf/commit/0dc4ee7537f3b12350f5966cecacd59bba840ec6","url":"https://github.com/espressif/esp-idf/commit/0dc4ee7537f3b12350f5966cecacd59bba840ec6"},{"category":"external","summary":"https://github.com/espressif/esp-idf/commit/37508ab91124ef426a7396d30f79eba1162700c7","url":"https://github.com/espressif/esp-idf/commit/37508ab91124ef426a7396d30f79eba1162700c7"},{"category":"external","summary":"https://github.com/espressif/esp-idf/commit/9fc0ca13b3b85b98d32b98cd9dc8ff9d82642b7b","url":"https://github.com/espressif/esp-idf/commit/9fc0ca13b3b85b98d32b98cd9dc8ff9d82642b7b"},{"category":"external","summary":"https://github.com/espressif/esp-idf/commit/dc46dc51359749e50617eb70d6f9ae298adc4fff","url":"https://github.com/espressif/esp-idf/commit/dc46dc51359749e50617eb70d6f9ae298adc4fff"},{"category":"external","summary":"https://github.com/espressif/esp-idf/commit/f88a47e4f37fb11ae4b0908cd5c80059d83198c6","url":"https://github.com/espressif/esp-idf/commit/f88a47e4f37fb11ae4b0908cd5c80059d83198c6"}]},"product_tree":{"branches":[{"category":"vendor","name":"espressif","branches":[{"category":"product_name","name":"esp-idf","branches":[{"category":"product_version","name":"= 6.0","product":{"name":"espressif esp-idf = 6.0","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:espressif:esp-idf:*:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"= 5.5.4","product":{"name":"espressif esp-idf = 5.5.4","product_id":"CSAFPID-2","product_identification_helper":{"cpe":"cpe:2.3:a:espressif:esp-idf:*:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"= 5.4.4","product":{"name":"espressif esp-idf = 5.4.4","product_id":"CSAFPID-3","product_identification_helper":{"cpe":"cpe:2.3:a:espressif:esp-idf:*:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"= 5.3.5","product":{"name":"espressif esp-idf = 5.3.5","product_id":"CSAFPID-4","product_identification_helper":{"cpe":"cpe:2.3:a:espressif:esp-idf:*:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"= 5.2.6","product":{"name":"espressif esp-idf = 5.2.6","product_id":"CSAFPID-5","product_identification_helper":{"cpe":"cpe:2.3:a:espressif:esp-idf:*:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-45541","title":"ESF-IDF: Remote Null Pointer Dereference in WebSocket Server","notes":[{"category":"description","text":"ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. In versions 5.2.6, 5.3.5, 5.4.4, 5.5.4, and 6.0, a NULL-pointer dereference exists in the WebSocket subprotocol-negotiation path of the esp_http_server component. While parsing the client-supplied Sec-WebSocket-Protocol request header during the WebSocket handshake, the tokenisation result is dereferenced without a NULL check, so a malformed header value can crash the server before any application-level authentication runs. This issue has been patched in versions 5.2.7, 5.3.6, 5.4.5, 5.5.5, and 6.0.1.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1","CSAFPID-2","CSAFPID-3","CSAFPID-4","CSAFPID-5"]},"scores":[{"cvss_v3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"products":["CSAFPID-1","CSAFPID-2","CSAFPID-3","CSAFPID-4","CSAFPID-5"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1","CSAFPID-2","CSAFPID-3","CSAFPID-4","CSAFPID-5"]}]}]}