netty-incubator-codec-ohttp is the OHTTP implementation for netty. BoringSSLAEADContext keeps track of how many OHTTP responses have been sent and uses this sequence number to calculate the appropriate nonce to use with the encryption algorithm. Unfortunately, two separate errors combine which would allow an attacker to cause the sequence number to overflow and thus the nonce to repeat.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.