Source: python-cryptography Version: 47.0.0-1 Severity: important Tags: security upstream X-Debbugs-Cc: [email protected], Debian Security Team <[email protected]>
Hi, The following vulnerability was published for python-cryptography. CVE-2026-69247[0]: | cryptography is a package designed to expose cryptographic | primitives and recipes to Python developers. From 44.0.0 until | 50.0.0, pkcs7_decrypt_der, pkcs7_decrypt_pem, and | pkcs7_decrypt_smime reported the outcome of decrypting a | RecipientInfo's encryptedKey in several distinguishable ways, one of | which disclosed the exact length recovered from the RSA operation. | The same distinction was also observable by timing. An application | that decrypts attacker-supplied EnvelopedData and reflects the | outcome gives the attacker a Bleichenbacher oracle against the | content-encryption key. Decryption ran as RSA PKCS#1 v1.5 decrypt of | encryptedKey, build an AES cipher from the result, then AES-CBC | decrypt and PKCS#7 unpad. Invalid RSA padding, a valid padding with | a bad key length, a correct length with a wrong key, and the real | key each failed or succeeded differently. Case 1 is reachable only | where the linked library lacks implicit rejection: OpenSSL 3.0 and | 3.1, LibreSSL, and BoringSSL. Exploitation requires a service that | auto-decrypts untrusted EnvelopedData matching the victim | certificate and answers adaptively at high volume, such as an S/MIME | gateway or mail filter. This issue is fixed in 50.0.0. If you fix the vulnerability please also make sure to include the CVE (Common Vulnerabilities & Exposures) id in your changelog entry. For further information see: [0] https://security-tracker.debian.org/tracker/CVE-2026-69247 https://www.cve.org/CVERecord?id=CVE-2026-69247 [1] https://github.com/pyca/cryptography/security/advisories/GHSA-g6cj-pr64-35w5 [2] https://github.com/pyca/cryptography/pull/15369 [3] https://github.com/pyca/cryptography/commit/53fccd93413a8d7f07d6d8999681f27b75cffa3f Please adjust the affected versions in the BTS as needed. Regards, Salvatore
