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OpensshApplication · OpenBSD

CVE-2023-28531

CRITICAL · 9.8 CVSS v3.1 Published 2023-03-17
Fix available
A fix is available. Upgrade to 9.3 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
ssh-add in OpenSSH before 9.3 adds smartcard keys to ssh-agent without the intended per-hop destination constraints. The earliest affected version is 8.9.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

ssh-add in OpenSSH versions before 9.3 adds smartcard keys to ssh-agent without the intended per-hop destination constraints that should limit key usage to specific network hops. This allows smartcard keys to be used beyond their intended scope, potentially enabling unauthorized access to systems that should not be accessible with those credentials.

MitigationUpgrade OpenSSH to version 9.3 or later to remediate this vulnerability. Alternatively, avoid using ssh-add with smartcard keys until the upgrade can be performed.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
OpensshApplication
Affected:>= 8.9, < 9.3
Brocade Fabric Operating SystemOperating system
Affected:all versions
Hci Bootstrap OsOperating system
Affected:all versions
Solidfire Element OsOperating system
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check OpenSSH version
    Run 'ssh-add -V' or 'ssh -V' to display the version number
    Affected if The version shown is 8.9 or higher but lower than 9.3
  2. Verify smartcard key usage with ssh-agent
    Run 'ssh-add -l' to list keys currently loaded in the ssh-agent; look for entries indicating smartcard/piv tokens (often contain 'card' or 'PIV' in the comment)
    Affected if Any keys listed are from a smartcard and the OpenSSH version is in the vulnerable range
  3. Confirm if ssh-add has been used with smartcards
    Check shell history or audit logs for commands like 'ssh-add -s <reader>' or 'ssh-add -e <reader>' which indicate smartcard key operations
    Affected if Smartcard key operations using ssh-add have been performed and OpenSSH version is vulnerable
  4. Identify NetApp product installations
    For NetApp systems, run 'sysctl -a' or check '/etc/os-release' to identify the NetApp product (Brocade Fabric OS, HCI Bootstrap OS, or Solidfire Element OS)
    Affected if Any of these NetApp products are running - all versions are affected per the advisory

A user is affected if they run OpenSSH versions 8.9 through 9.2 and have used ssh-add with smartcard keys, or if they run any version of the listed NetApp products.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 9.3 or later
Fixed in 9.3
Interim mitigation

Upgrade OpenSSH to version 9.3 or later to remediate this vulnerability. Alternatively, avoid using ssh-add with smartcard keys until the upgrade can be performed.

Recommended fix High confidence

OpenSSH 9.3 or later

  1. Verify current OpenSSH version using 'ssh -V' or 'ssh-add -V'
  2. Download OpenSSH 9.3 or later from official upstream (www.openssh.com) or your distribution's package repository
  3. For source compilation: extract tarball, run './configure', 'make', 'make install'
  4. For package managers: use 'apt-get update && apt-get install openssh-client' (Debian/Ubuntu), 'dnf update openssh' (Fedora), or 'emerge --ask net-misc/openssh' (Gentoo)
  5. Restart ssh-agent if running: 'eval "$(ssh-agent -s)"'
  6. Verify fix by running 'ssh-add -l' to confirm smartcard keys are now handled with per-hop destination constraints

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Openssh Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-28531 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data