Answer in brief
CVE-2026-69247 records a High severity (CVSS 8.2) vulnerability in cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing. The current sources do not mark it as known exploited. The current feed maps cryptography (pip), cryptography (pypi). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps cryptography (pip), cryptography (pypi). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| cryptographypip | >=44.0.0,<50.0.0 | 50.0.0 |
| cryptographypypi | >=44.0.0 <50.0.0 | 50.0.0 |
Published upstream
Aug 3, 2026
Evidence: source:ghsa:source_dates:source-dates:recordSource modified
Oct 23, 2026
Evidence: source:ghsa:source_dates:source-dates:recordFirst seen by HOL
Aug 3, 2026
### Summary `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. Introduced in 44.0.0. Fixed in 50.0.0. ### Details Decryption ran as: RSA PKCS#1 v1.5 decrypt of `encryptedKey` → build an AES cipher from the result → AES-CBC decrypt and PKCS#7 unpad. Each stage failed differently, with no RFC 3218 mitigation: 1. invalid RSA padding → `Decryption failed` 2. valid padding, bad key length → `Invalid key size (N) for AES.`, disclosing `N` 3. correct length, wrong key → `Invalid padding bytes.` 4. the real key → plaintext Case 1 is reachable only where the linked library lacks implicit rejection: OpenSSL 3.0 and 3.1, LibreSSL, and BoringSSL. On OpenSSL 3.2+, used in our wheels, invalid padding instead returns a synthetic plaintext of pseudorandom length, so the error channel does not distinguish conforming ciphertexts. 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. ### Fix Per RFC 3218, the content-encryption algorithm is now resolved before the private key is used, so the expected key length is known in advance. If the RSA decryption fails or recovers a key of the wrong length, a random key of the expected length is substituted and decryption continues down an identical path. All failures now report identically and perform the same work. ### Not addressed by this fix `EnvelopedData` does not authenticate its content. Tampering with `encryptedContent` alone yields a CBC padding oracle that recovers plaintext at roughly 256 queries per byte, without recovering any key, on every backend. This is a property of PKCS#7 rather than of this implementation, cannot be fixed in the library, and is now documented. ### Credit Reported by @X1AOxiang.
Quoted source text, attributed separately from HOL analysis.