Weaknesses in the generation of TCP/UDP source ports and some other header values in Google's gVisor allowed them to be predicted by an external attacker in some circumstances.
https://github.com/google/gvisor/commit/cbdb2c61b1f753834cedf2ebe68cbc335dadca52
https://github.com/google/gvisor/commit/83f75082e5b03fafca9201d9d9939028f712b0b2
https://github.com/google/gvisor/commit/5d2bf2546805afa09a6f6d9b23ec267823e32205