iText v7.1.17, up to (exluding)": 7.1.18 and 7.2.2 was discovered to contain an out-of-memory error via the component readStreamBytesRaw, which allows attackers to cause a Denial of Service (DoS) via a crafted PDF file.
iText v7.1.17 was discovered to contain a stack-based buffer overflow via the component ByteBuffer.append, which allows attackers to cause a Denial of Service (DoS) via a crafted PDF file.
The XML parsers in iText before 5.5.12 and 7.x before 7.0.3 do not disable external entities, which might allow remote attackers to conduct XML external entity (XXE) attacks via a crafted PDF.