{"metadata": {"vulnerability": "CVE-2026-76787", "count": 10, "kinds": {"milestone": 3, "sighting": 1, "kev": 0, "other": 6}}, "data": [{"timestamp": "2026-08-19T17:53:24.899Z", "date_only": false, "value": "2026-08-19T17:53:24.899Z", "kind": "milestone", "label": "Reserved", "source": "cvelistv5", "record": "CVE-2026-76787", "field": "cveMetadata.dateReserved"}, {"timestamp": "2026-10-19T20:39:20.425Z", "date_only": false, "value": "2026-10-19T20:39:20.425Z", "kind": "milestone", "label": "Published", "source": "cvelistv5", "record": "CVE-2026-76787", "field": "cveMetadata.datePublished"}, {"timestamp": "2026-10-19T20:39:20.425Z", "date_only": false, "value": "2026-10-19T20:39:20.425Z", "kind": "other", "label": "Updated", "source": "cvelistv5 / zephyr", "record": "CVE-2026-76787", "field": "containers.cna.providerMetadata.dateUpdated"}, {"timestamp": "2026-10-19T20:44:27.670Z", "date_only": false, "value": "2026-10-19T20:44:27.670163Z", "kind": "sighting", "label": "Seen", "source": "https://infosec.exchange/users/cve/statuses/117469522626694963", "record": "CVE-2026-76787", "field": "creation_timestamp", "uuid": "0f4cbd52-ca18-4e69-8fb9-453ac2b567a2", "content": "CVE-2026-76787 NULL pointer dereference in the UpdateHub FOTA client when probe metadata omits sha256sum The UpdateHub firmware-over-the-air client parses the CoAP probe response with Zephyr's JSON library in z_impl_updatehub_probe() (subsys/mgmt/updatehub/updatehub.c). The decoder treats every descriptor field as optional \u2014 json_obj_parse() returns a bitmask of the fields it actually decoded and never fails on a missing one \u2014 so a response that omits the \"sha256sum\" string leaves the corresponding const char * in the zero-initialised struct resp_probe_any_boards / struct resp_probe_some_boards at NULL. Both metadata branches then computed sha256size = strlen(...objects.sha256sum) + 1 before any validation, dereferencing that NULL pointer; the SHA256_HEX_DIGEST_SIZE test that follows operates on a value the bad read has already produced and cannot prevent it.\nThe metadata is supplied entirely by the network peer: probe_cb() accepts the datagram, runs coap_packet_parse() and copies the payload with no token matching and no cryptographic check. With CONFIG_UPDATEHUB_DTLS unset \u2014 the default \u2014 start_coap_client() uses plain CoAP over UDP on port 5683 with no peer authentication and resolves the server via unauthenticated DNS, so an on-path attacker, a DNS spoofer, or an off-path attacker who wins the race with a forged source address can deliver the malformed metadata. A probe response as simple as \"objects\":[[{}],[{}]] suffices, and no user interaction is required because updatehub_autohandler() polls on CONFIG_UPDATEHUB_POLL_INTERVAL. When CONFIG_UPDATEHUB_DTLS=y the trigger narrows to a malicious or compromised update server.\nThe primitive is a read at address zero, not a write, so the impact is availability only. On targets where the low address range is unmapped or protected \u2014 MMU-based architectures, builds with CONFIG_NULL_POINTER_EXCEPTION_DETECTION_DWT/_MPU/_PMP, TrustZone non-secure images, and SoCs such as nRF54L whose 0x0\u20130x400 window is unmapped \u2014 the load faults and Zephyr's default fatal handler halts the system, giving a remotely re-triggerable denial of service on every poll. On classic Cortex-M targets where the vector table is readable at address zero the walk usually terminates immediately and the request is rejected by the length check, so the outcome is configuration- and SoC-dependent. There is no memory write, and the copied bytes are only compared against the locally computed image hash, so there is no information-disclosure channel.\nThe fix adds an explicit sha256sum == NULL test that returns UPDATEHUB_METADATA_ERROR ahead of the strlen() in both metadata branches. Debug builds (CONFIG_UPDATEHUB_LOG_LEVEL=4) still format the same pointers with %s in a LOG_DBG() loop that runs before the new checks, so that variant remains in debug configurations only.\nhttps://www.cve.org/CVERecord?id=CVE-2026-76787https://github.com/zephyrproject-rtos/zephyr/commit/6fc4f27a74021b52c509e4f7912d68145dfa7728https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-82gq-cmqw-xgx2#zephyrproject #zephyr#CVE_2026_76787#bot", "url": "https://infosec.exchange/users/cve/statuses/117469522626694963"}, {"timestamp": "2026-10-19T21:18:01.230Z", "date_only": false, "value": "2026-10-19T21:18:01.230", "kind": "milestone", "label": "Published", "source": "fkie_nvd \u00b7 FKIE_CVE-2026-76787", "record": "FKIE_CVE-2026-76787", "field": "published"}, {"timestamp": "2026-10-20T18:04:36.017Z", "date_only": false, "value": "2026-10-20T18:04:36.017568Z", "kind": "other", "label": "Recorded", "source": "cvelistv5 / CISA-ADP", "record": "CVE-2026-76787", "field": "containers.adp.0.metrics.0.other.content.timestamp"}, {"timestamp": "2026-10-20T18:04:36.017Z", "date_only": false, "value": "2026-10-20T18:04:36.017568Z", "kind": "other", "label": "Recorded", "source": "fkie_nvd \u00b7 FKIE_CVE-2026-76787", "record": "FKIE_CVE-2026-76787", "field": "metrics.ssvcV203.0.ssvcData.timestamp"}, {"timestamp": "2026-10-20T18:08:01.790Z", "date_only": false, "value": "2026-10-20T18:08:01.790Z", "kind": "other", "label": "Updated", "source": "cvelistv5", "record": "CVE-2026-76787", "field": "cveMetadata.dateUpdated"}, {"timestamp": "2026-10-20T18:08:01.790Z", "date_only": false, "value": "2026-10-20T18:08:01.790Z", "kind": "other", "label": "Updated", "source": "cvelistv5 / CISA-ADP", "record": "CVE-2026-76787", "field": "containers.adp.0.providerMetadata.dateUpdated"}, {"timestamp": "2026-10-20T19:59:00.607Z", "date_only": false, "value": "2026-10-20T19:59:00.607", "kind": "other", "label": "Updated", "source": "fkie_nvd \u00b7 FKIE_CVE-2026-76787", "record": "FKIE_CVE-2026-76787", "field": "lastModified"}]}