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.

The defect was introduced in commit 7bd9a8dc356aae756b40755be76d36205b6b161a where initialization logic inside encrypted_build_skesk() only randomized the key for the SKESK path and omitted it for the PKESK path.

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.

The defect was introduced in commit 7bd9a8dc356aae756b40755be76d36205b6b161a where initialization logic inside encrypted_build_skesk() only randomized the key for the SKESK path and omitted it for the PKESK path.

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.

The defect was introduced in commit 7bd9a8dc356aae756b40755be76d36205b6b161a where initialization logic inside encrypted_build_skesk() only randomized the key for the SKESK path and omitted it for the PKESK path.

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.

The defect was introduced in commit 7bd9a8dc356aae756b40755be76d36205b6b161a where initialization logic inside encrypted_build_skesk() only randomized the key for the SKESK path and omitted it for the PKESK path.

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.

The defect was introduced in commit 7bd9a8dc356aae756b40755be76d36205b6b161a where initialization logic inside encrypted_build_skesk() only randomized the key for the SKESK path and omitted it for the PKESK path.

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. The defect was introduced in commit 7bd9a8dc356aae756b40755be76d36205b6b161a where initialization logic inside encrypted_build_skesk() only randomized the key for the SKESK path and omitted it for the PKESK path.

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. The defect was introduced in commit 7bd9a8dc356aae756b40755be76d36205b6b161a where initialization logic inside encrypted_build_skesk() only randomized the key for the SKESK path and omitted it for the PKESK path.

These are all security issues fixed in the librnp0-0.18.1-1.1 package on the GA media of openSUSE Tumbleweed.

This update for rnp fixes the following issues:

• update to 0.18.1:
  • CVE-2025-13470: PKESK (public-key encrypted) session keys were generated as all-zero, allowing trivial decryption of messages encrypted with public keys only (boo#1253957, CVE-2025-13402)