CVE-2019-1563: Padding Oracle in PKCS7_dataDecode and CMS_decrypt_set1_pkey

Severity: low (CVSS 3.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 3.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-09-10 · updated 2026-10-08
Weakness: CWE-203

Description

In situations where an attacker receives automated notification of the success or failure of a decryption attempt an attacker, after sending a very large number of messages to be decrypted, can recover a CMS/PKCS7 transported encryption key or decrypt any RSA encrypted message that was encrypted with the public RSA key, using a Bleichenbacher padding oracle attack. Applications are not affected if they use a certificate together with the private RSA key to the CMS_decrypt or PKCS7_decrypt functions to select the correct recipient info to decrypt. Fixed in OpenSSL 1.1.1d (Affected 1.1.1-1.1.1c). Fixed in OpenSSL 1.1.0l (Affected 1.1.0-1.1.0k). Fixed in OpenSSL 1.0.2t (Affected 1.0.2-1.0.2s).

Affected products

OpenSSL: from 1.0.2 through 1.0.2s; from 1.1.0 through 1.1.0k; from 1.1.1 through 1.1.1c

References

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