The vulnerability resides in the JweDirectDecryptorBlock.Decrypt function, where an unchecked 64-bit length from the _thales_aad protected-header field is read without verification. If an attacker forges this header, the routine can trigger a binary.BigEndian.Uint64 panic on truncation, allocate an unbounded buffer when the length is excessively large, or cause a slice-bounds panic when the value exceeds the size of the decrypted payload. These failures abort the decryption process and can lead to denial of service by exhausting system resources or crashing the application.

The affected product is Eclipse KeyPont GOSE, distributed by the Eclipse Foundation. No specific version information is disclosed in the advisory, so all releases of GOSE that include the vulnerable JweDirectDecryptorBlock implementation are potentially impacted until a patch is applied.

The CVSS score of 6.3 indicates medium severity. Because a crafted decryption request can be sent remotely to the GOSE service, the likely attack vector is network based. The EPSS score is unavailable, and the vulnerability is not listed in CISA KEV, suggesting no widespread active exploitation is known. Nevertheless, the possibility of causing a crash or unbounded allocation presents a tangible risk to availability.