Information Exposure Through an Error Message in python-cryptography - #VU140695
Published: August 1, 2026
Vulnerability identifier: #VU140695
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: N/A
CWE-ID: CWE-209
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Affected software:
python-cryptography
python-cryptography
Detailed vulnerability description
The vulnerability allows a remote attacker to recover plaintext from PKCS#7 EnvelopedData messages.
The vulnerability exists due to generation of error message containing sensitive information and observable timing discrepancy in pkcs7_decrypt_der, pkcs7_decrypt_pem, and pkcs7_decrypt_smime when decrypting attacker-supplied EnvelopedData. A remote attacker can send crafted EnvelopedData messages and observe distinguishable errors and timing differences to recover plaintext from PKCS#7 EnvelopedData messages.
Exploitation requires a service that automatically decrypts untrusted EnvelopedData for the victim certificate and returns adaptive responses at high volume.
Remediation
Install security update from vendor's website.