CVE-2025-13470

In RNP version 0.18.0 a refactoring regression causes the symmetric 

session key used for Public-Key Encrypted Session Key (PKESK) packets to

 be left uninitialized except for zeroing, resulting in it always being 

an all-zero byte array.

Any data encrypted using public-key encryption 

in this release can be decrypted trivially by supplying an all-zero 

session key, fully compromising confidentiality.

The vulnerability affects only public key encryption (PKESK packets).  Passphrase-based encryption (SKESK packets) is not affected.

Root cause: Vulnerable session key buffer used in PKESK packet generation.

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The defect was introduced in commit 7bd9a8dc356aae756b40755be76d36205b6b161a where initialization 

logic inside encryptedbuildskesk() only randomized the key for the 

SKESK path and omitted it for the PKESK path.