CVE-2026-69247
published 2026-08-03CVE-2026-69247: 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…
PriorityP344high8.2CVSS 4.0
AVNACHATPPRNUINVCHVINVANSCNSINSANEXCRXIRXARXMAVXMACXMATXMPRXMUIXMVCXMVIXMVAXMSCXMSIXMSAXSXAUXRXVXREXUX
EPSS
0.27%
19.6th percentile
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.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| cryptography.io | cryptography | >= 44.0.0 < 50.0.0 | 50.0.0 |
| debian | python-cryptography | — | — |
| pyca | cryptography | — | — |
| ubuntu | python-cryptography | — | — |
CVSS provenance
nvdv4.08.2HIGHCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vendor_redhat8.2HIGH
vendor_ubuntu6.5MEDIUM
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GHSA
cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing
ghsa·2026-08-03
CVE-2026-69247 [HIGH] CWE-208 cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing
cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing
### 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 fa
VulDB
pyca cryptography up to 49.x information disclosure
vuldb·2026-08-03·CVSS 8.2
CVE-2026-69247 [HIGH] pyca cryptography up to 49.x information disclosure
A vulnerability, which was classified as problematic, has been found in pyca cryptography up to 49.x. Impacted is the function pkcs7_decrypt_der/pkcs7_decrypt_pem/pkcs7_decrypt_smime. This manipulation causes information disclosure.
This vulnerability is tracked as CVE-2026-69247. The attack is possible to be carried out remotely. No exploit exists.
It is advisable to upgrade the affected component.
Ubuntu
python-cryptography vulnerabilities
vendor_ubuntu·2026-09-16·CVSS 6.5
CVE-2026-69249 [MEDIUM] python-cryptography vulnerabilities
Title: python-cryptography vulnerabilities
Summary: Several security issues were fixed in python-cryptography.
It was discovered that python-cryptography incorrectly accepted objects
with immutable buffers when performing certain cipher operations. This
would result in corrupted output, contrary to expectations. This issue only
affected Ubuntu 18.04 LTS. (CVE-2023-23931)
It was discovered that python-cryptography reported the outcome of
decrypting PKCS#7 enveloped data in distinguishable ways, and with
observable timing differences. A remote attacker could possibly use this
issue to recover the key used to encrypt the message contents, and obtain
sensitive information. This issue only affected Ubuntu 26.04 LTS.
(CVE-2026-69247)
Jack Lloyd discovered that python-cryptography incorrectly
Red Hat
python-cryptography: python-cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing
vendor_redhat·2026-08-03·CVSS 8.2
CVE-2026-69247 [HIGH] CWE-208 python-cryptography: python-cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing
python-cryptography: python-cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing
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 A
No detection rules found.
No public exploits indexed.
2026-08-03
Published