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FedoraOperating system · Fedoraproject

CVE-2023-45239

CRITICAL · 9.8 CVSS v3.1 Published 2023-10-06
Fix available
A fix is available. Upgrade to 2023-10-05 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click Patch available

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
A lack of input validation exists in tac_plus prior to commit 4fdf178 which, when pre or post auth commands are enabled, allows an attacker who can control the username, rem-addr, or NAC address sent to tac_plus to inject shell commands and gain remote code execution on the tac_plus server.

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

A detailed technical summary for this CVE is being prepared.

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
FedoraOperating system
Affected:= 39
Tac PlusApplication
Affected:< 2023-10-05

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

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 2023-10-05 or later
Fixed in 2023-10-05
Vendor patch github.com →
Recommended fix High confidence

tac_plus version after 2023-10-05 (or commit 4fdf178)

  1. 1. Identify if pre-auth or post-auth commands are configured in /etc/tacacs/tac_plus.conf (look for 'Authorization' or 'Authentication' commands sections)
  2. 2. As an immediate mitigation, disable any pre-auth or post-auth command configurations if they are not strictly necessary
  3. 3. For Fedora 39 systems, update the tac_plus package: run 'sudo dnf update tac-plus' or 'sudo dnf upgrade tac-plus'
  4. 4. If the package is not available via DNF, download and compile tac_plus from source after commit 4fdf178 (https://github.com/facebook/tac_plus/commit/4fdf178)
  5. 5. Alternatively, apply the patch from PR #41 (https://github.com/facebook/tac_plus/pull/41) to the source code
  6. 6. Restart the tac_plus service after upgrading: 'sudo systemctl restart tacacs_plus'
  7. 7. Verify the service is running correctly: 'sudo systemctl status tacacs_plus'

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

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,300. Get the upgrade done

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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-2023-45239 in production — separate from our analysis above.

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What this is

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  • Version or environment caveats, and links to real fixes
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