CVE-2022-4087: 
Linux Red Hat vulnerability analysis and mitigation

A vulnerability was discovered in iPXE's TLS implementation, specifically in the tls_new_ciphertext function within src/net/tls.c. The vulnerability was assigned CVE-2022-4087 and relates to how the system handles block padding in TLS communications (GitHub Commit).

The vulnerability exists in the TLS implementation where invalid block padding was not properly handled, potentially leading to timing attacks. The issue specifically occurs in the tls_new_ciphertext function where the system previously returned immediately upon detecting invalid padding. The fix involves treating invalid block padding as zero-length padding to defer the failure until after computing the incorrect MAC, thereby hardening against padding oracle attacks (GitHub Commit).

The vulnerability has been patched by modifying the handling of invalid block padding. Instead of immediately returning an error when invalid padding is detected, the system now treats it as zero-length padding and continues processing. This change helps prevent timing-based attacks by ensuring consistent processing time regardless of padding validity (GitHub Commit).