Improper Validation of Integrity Check Value Affecting org.bouncycastle:bcprov-debug-jdk18on package, versions [,1.85)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published5 Aug 2026
- disclosed3 Aug 2026
- creditUnknown
Introduced: 3 Aug 2026
NewCVE-2026-12803 (opens in a new tab)How to fix?
Upgrade org.bouncycastle:bcprov-debug-jdk18on to version 1.85 or higher.
Overview
Affected versions of this package are vulnerable to Improper Validation of Integrity Check Value in the processPacket() method of KCCMBlockCipher, which invokes processAAD() only when associated data is present, so with no AAD the G1 block (nonce, length, flag) is never mixed into the MAC and the tag reduces to a CBC-MAC over the ciphertext alone, independent of the nonce. An attacker with encryption-oracle access can assemble a valid ciphertext and tag for any never-queried plaintext and nonce pair by deriving the data and tag keystreams from two nonces. This affects only DSTU 7624 CCM encryption performed without any associated data, and requires chosen-plaintext access to an encryption oracle.