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CVE-2026-16001: Product identification pending

Severity

8.2 (HIGH)

Affected versions

Before 2.7.0

Fixed version

2.7.0

Patch status

Patched

Published

2026-10-02T07:16:36.537

Modified

2026-10-02T07:16:36.537

Why it matters

High-severity vulnerability requiring prioritized review.

Recommended admin actions

• Review and patch based on exposure, asset criticality, and business impact.
• Compare installed versions against the affected version range in the advisory.
• Treat internet-facing systems as higher priority.

Technical summary

Exposure of the message authentication key through the encryption keystream in the stream mode of IesEngine (an IesEngine constructed without a block cipher) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who has observed one encrypted message with known plaintext to forge shorter messages of their choosing that the recipient accepts as authentic, via a crafted ciphertext and MAC tag, because the MAC key was taken from the key derivation output directly after a keystream as long as the message, while the derivation input depends only on the static key pair and fixed parameters. The keystream revealed by that one message therefore contains the MAC key for every sufficiently shorter message.

View the official NVD record for CVE-2026-16001

CVE data is sourced from NVD/CNA records and optional enrichment. Validate against the vendor advisory before taking production action.