Covert Channel Affecting openssl package, versions [0,]
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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Test your applications- Snyk IDSNYK-CONAN-OPENSSL-17276892
- published10 Jun 2026
- disclosed9 Jun 2026
- creditAlex Gaynor
Introduced: 9 Jun 2026
NewCVE-2026-42768 (opens in a new tab)How to fix?
A fix was pushed into the master branch but not yet published.
Overview
Affected versions of this package are vulnerable to Covert Channel information exposure from CMS_decrypt() and PKCS7_decrypt(). An attacker who can supply CMS or S/MIME messages and observe the application's error code and/or decryption output can use the victim's process as an adaptive chosen ciphertext oracle to decrypt arbitrary RSA ciphertexts or forge PKCS#1 v1.5 signatures under the victim's private key, exploitable either by authoring a message with a second probe KTRI when no recipient certificate is supplied (the API iterates every KTRI rather than stopping at the first success) or, when a recipient certificate is supplied but not matched, by distinguishing the substituted random key.
Note: The attack requires an application that exposes both the message input and the relevant side channel to a remote attacker, and the project maintainers are aware of no such application.