| Name | CVE-2026-69247 |
| Description | 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. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| Debian Bugs | 1143596 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| python-cryptography (PTS) | bullseye | 3.3.2-1 | fixed |
| bullseye (security) | 3.3.2-1+deb11u1 | fixed | |
| bookworm | 38.0.4-3+deb12u1 | fixed | |
| bookworm (security) | 38.0.4-3~deb12u1 | fixed | |
| trixie | 43.0.0-3+deb13u1 | fixed | |
| forky | 47.0.0-1 | vulnerable | |
| sid | 49.0.0-2 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| python-cryptography | source | bullseye | (not affected) | |||
| python-cryptography | source | bookworm | (not affected) | |||
| python-cryptography | source | trixie | (not affected) | |||
| python-cryptography | source | (unstable) | 49.0.0-2 | 1143596 |
[trixie] - python-cryptography <not-affected> (Vulnerable code introduced later)
[bookworm] - python-cryptography <not-affected> (Vulnerable code introduced later)
[bullseye] - python-cryptography <not-affected> (Vulnerable code introduced later)
https://github.com/pyca/cryptography/security/advisories/GHSA-g6cj-pr64-35w5
https://github.com/pyca/cryptography/pull/15369
Fixed by: https://github.com/pyca/cryptography/commit/53fccd93413a8d7f07d6d8999681f27b75cffa3f (50.0.0)