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Fencer Vulns
high 8.2

CVE-2026-69247 json

cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing

published 2026-08-03 3 mo ago modified 2026-10-23 16 d ago also GHSA-g6cj-pr64-35w5 , PYSEC-2026-3552 , EUVD-2026-52446

cvss
8.2
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi cryptography 50.0.0
  • python-cryptography Debian 14 49.0.0-2

debian advisories DEBIAN-CVE-2026-69247

  • python-cryptography Ubuntu 26.04 LTS 46.0.5-1ubuntu2.2

ubuntu advisories UBUNTU-CVE-2026-69247

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python-cryptography hummingbird 1 50.0.0-1.hum1
  • python3-cryptography hummingbird 1 50.0.0-1.hum1

red hat advisories RHSA-2026:55543

  • python-cryptography SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 44.0.3-160000.5.1

suse advisories SUSE-SU-2026:23404-1SUSE-SU-2026:23570-1

  • python-cryptography openSUSE Leap 16.0 44.0.3-160000.5.1
  • python-cryptography openSUSE Tumbleweed 50.0.0-1.1

opensuse advisories openSUSE-SU-2026:21685-1openSUSE-SU-2026:11468-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-69247 updated cvss 5.9

python-cryptography: python-cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing

  • Red Hat Ansible Automation Platform 2 python-cryptography 46.0.7-3.el10ap, python3.12-cryptography 46.0.5-2.el9ap Red Hat Enterprise Linux 9 python3.14-cryptography, python3.14-cryptography 45.0.4-4.el10_2.5 Red Hat Enterprise Linux 10 python-cryptography 46.0.7-3.el10ap, python3.14-cryptography 45.0.4-4.el10_2.5 Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9 Red Hat Satellite 6 python3-cryptography, python-cryptography 46.0.7-3.el10ap, python3.12-cryptography 46.0.5-2.el9ap
    affected: workaround, no fix available “Fix deferred”
  • Red Hat AI Inference Server 3.4 rhaii/vllm-cpu-rhel9 1790075793, rhaii/vllm-cuda-rhel9 1790090131, rhaii/vllm-rocm-rhel9 1790109620, rhaii/vllm-spyre-rhel9 1790076141
    fixed: vendor fix RHSA-2026:70965
  • Red Hat Hardened Images python-cryptography 50.0.0-1.hum1, python3-cryptography 50.0.0-1.hum1
    fixed: vendor fix RHSA-2026:55543
  • Red Hat Ansible Automation Platform 2 python3x-cryptography 42.0.5-1.el8ap, python3.11-cryptography 42.0.5-1.el8ap Red Hat Enterprise Linux 8 python3-cryptography, python-cryptography 46.0.7-3.el10ap, python3.12-cryptography 46.0.5-2.el9ap Red Hat Enterprise Linux 9 python3-cryptography, python3.12-cryptography, python-cryptography 46.0.7-3.el10ap, python3.12-cryptography 46.0.5-2.el9ap
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CNA 4.0 8.2 CVSS: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

Affected packages

ecosystem package affected fixed in
pypi cryptography
>=44.0.0, <50.0.0
50.0.0

Affected products

  • pyca cryptography

Classification

Weakness
  • CWE-208 Observable Timing Discrepancy
  • CWE-209 Generation of Error Message Containing Sensitive Information

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.