The vulnerability in Apache Thrift C++ THeaderTransport arises when the ZLIB transform is enabled for frames. The transform() method copies compressed data into a write buffer without ensuring the buffer is large enough. Since some data may grow after compression (e.g., data supplied by a remote peer), this can cause a heap-based buffer overflow by writing past the end of the allocated buffer. Additionally, for large frames, it can read past the end of the transform buffer. This flaw affects Apache Thrift versions prior to 0.25.0 and is addressed by upgrading to version 0.25.0.

Exploitation of this vulnerability can lead to heap-based buffer overflow conditions, which may allow an attacker to cause application crashes or potentially execute arbitrary code. The vulnerability is critical due to the possibility of remote exploitation without authentication and the high impact on confidentiality, integrity, and availability.

Users should upgrade Apache Thrift to version 0.25.0 or later, where this vulnerability is fixed. No other mitigations are indicated. Patch status is confirmed by the vendor advisory recommending upgrade to 0.25.0.