From 15cc805c044f2d150e0ad222e2b66433c78e41d0 Mon Sep 17 00:00:00 2001 From: Wessel Nieboer Date: Wed, 11 Feb 2026 03:19:13 +0100 Subject: [PATCH] fix bounds check on PAYLOAD_TYPE_PATH decrypted data The path_len field inside the decrypted PATH payload was used to advance the parse cursor without validating it against the actual decrypted data length. A malicious peer sharing a key could craft a PATH packet with an oversized path_len, causing out-of-bounds reads past the decrypted buffer when accessing the extra_type byte and extra data pointer. Add a bounds check after reading path_len to ensure the decrypted buffer contains enough bytes for the claimed path plus the mandatory extra_type byte before dereferencing. --- src/Mesh.cpp | 1 + 1 file changed, 1 insertion(+) diff --git a/src/Mesh.cpp b/src/Mesh.cpp index 57fee140..afc46df1 100644 --- a/src/Mesh.cpp +++ b/src/Mesh.cpp @@ -155,6 +155,7 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) { uint8_t path_len = data[k++]; uint8_t hash_size = (path_len >> 6) + 1; uint8_t hash_count = path_len & 63; + if (k + hash_size*hash_count + 1 > len) break; // bounds check: need path bytes + extra_type byte uint8_t* path = &data[k]; k += hash_size*hash_count; uint8_t extra_type = data[k++] & 0x0F; // upper 4 bits reserved for future use uint8_t* extra = &data[k];