IBM Aspera Shares CVE-2025-13916

Applies to IBM Aspera Shares versions 1.9.9 through 1.11.0 where a weaker-than-expected cryptographic algorithm is used to protect sensitive data. Realistic exploitation requires the attacker to first acquire the encrypted material - via an on-path/man-in-the-middle position on network traffic, captured session data, or access to data at rest - before the weak cipher can be broken; the CVE text does not name the specific algorithm or protocol. Limiting factors: impact is confidentiality only (no integrity or availability effect), a fixed version is available from IBM, and EPSS (0.02%) plus SSVC (Exploitation: none) indicate no observed or automatable exploitation.

Signals align toward LOW real-world urgency despite the 7.5 'High' CVSS. The vendor vector (AV:N/AC:L/PR:N/UI:N) scores confidentiality-only impact (C:H/I:N/A:N) from use of weak cryptographic algorithms (CWE-327). EPSS is 0.02% (5th percentile) - near the floor - and SSVC reads Exploitation: none, Automatable: no, Technical Impact: partial, with no CISA KEV listing and no public exploit identified. These low-exploitability signals are consistent with each other and with the nature of the flaw: weak crypto is not a single-request 'send packet, get code exec' bug. Notably, the AC:L/PR:N rating understates real difficulty - to 'decrypt highly sensitive information' an attacker must first OBTAIN the protected ciphertext (on-path interception, captured traffic, or access to data at rest) before the weak algorithm can be broken, which in practice implies added attack complexity and a network position. This is a mismatch worth verifying with IBM: the CVSS presents trivial network exploitation, but the description implies the attacker needs prior access to encrypted material. Net: a genuine confidentiality weakness in a patched product, but low priority absent broad exposure.

An attacker who can capture Aspera Shares traffic or access stored data protected by the affected weak algorithm (e.g. via a man-in-the-middle position on the network path or access to backups) retrieves the ciphertext and then cryptanalyzes or brute-forces it to recover highly sensitive plaintext. No authentication or user interaction is required to attempt decryption once the ciphertext is held, but no public exploit code exists and EPSS/SSVC indicate no observed exploitation.