{"cve":"CVE-2026-69247","nvd":{"published":"2026-08-03T22:16:52.380","modified":"2026-10-23T21:10:00.157","status":"Awaiting Analysis","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.","cvss_v4":{"vector":"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","score":8.2},"cvss_v3":null,"cwes":["CWE-208","CWE-209"],"references":["https://github.com/pyca/cryptography/commit/53fccd93413a8d7f07d6d8999681f27b75cffa3f","https://github.com/pyca/cryptography/pull/15369","https://github.com/pyca/cryptography/security/advisories/GHSA-g6cj-pr64-35w5"],"products":[],"source":"nvd","synced_at":"2026-10-24T16:53:34.184483516+00:00"},"epss":{"cve":"CVE-2026-69247","score":0.00274,"percentile":0.1964,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-g6cj-pr64-35w5","url":"https://osv.dev/vulnerability/GHSA-g6cj-pr64-35w5","summary":"cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing","modified":"2026-09-10T03:50:53.610446769Z","packages":[{"ecosystem":"PyPI","name":"cryptography","purl":"pkg:pypi/cryptography","ranges":[">=44.0.0 <50.0.0"],"fixed":["50.0.0"]}]},{"id":"PYSEC-2026-3552","url":"https://osv.dev/vulnerability/PYSEC-2026-3552","summary":"cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing","modified":"2026-08-04T14:30:15.036332054Z","packages":[{"ecosystem":"PyPI","name":"cryptography","purl":"pkg:pypi/cryptography","ranges":[">=44.0.0 <50.0.0"],"fixed":["50.0.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}