critical CVSS 9 EPSS 0.23%

CVE-2026-45408·Docker vulnerability

Dokku is a docker-powered PaaS. Prior to 0.38.2, the app name validation regex (^[a-z0-9][^/:_A-Z]*$) permits shell metacharacters. When an authenticated user pushes to a git remote with a crafted app name, the name is embedded unquoted into a bash pre-receive hook script via an unquoted heredoc (<<EOF instead of <<'EOF') in fn-git-create-hook() at plugins/git/internal-functions:378. On git push, bash interprets the semicolon as a command separator, executing arbitrary commands as the dokku user. This vulnerability is fixed in 0.38.2.

Severity
critical
Software
Docker
Fixed in
0.38.2
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at 0.23% — higher than 14% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Read the two together. CVE-2026-45408 scores 9 on CVSS, so a successful attack would be serious — but at 0.23%, almost nobody is currently attempting it. That is a different situation from a flaw under mass exploitation, and it is usually the difference between patching on your next maintenance window and patching tonight.

Affected versions

Until: 0.38.2

Fixed in: 0.38.2

How to fix this CVE

Upgrade Docker to version 0.38.2 or later to patch a critical command injection vulnerability in the git pre-receive hook validation logic. The vulnerability allows authenticated users to execute arbitrary commands by injecting shell metacharacters into specially crafted app names during git push operations. Immediate patching is strongly recommended for any Docker installations that support multi-user git-based deployments.

sudo dnf update docker-ce docker-ce-cli --advisory=GHSA-9x85-7gxq-fcr3

Defensia detects this vulnerability

What an exploitation attempt looks like

Sample log line indicative of exploitation attempts:

git push remote with app name pattern matching [a-z0-9][^/:_A-Z]*;.*|.*`.*|.*\$\(.*\) followed by pre-receive hook execution error or command execution in dokku user context

How to check if you are affected

  1. Run 'docker --version' and 'dokku version' to identify the currently installed version; compare against 0.38.2
  2. Check git pre-receive hook file at /var/lib/dokku/plugins/git/internal-functions for the vulnerable unquoted heredoc pattern (<<EOF)
  3. Search system audit logs for failed git push attempts with unusual app names containing semicolons, backticks, or dollar signs: grep -r 'git.*receive\|app.*name.*invalid' /var/log/auth.log /var/log/syslog
  4. Verify the patch by confirming the file uses quoted heredoc syntax (<<'EOF') in the fn-git-create-hook() function after upgrade

FAQ

What is CVE-2026-45408?

CVE-2026-45408 is a critical command injection flaw in Docker where insufficient input validation on app names allows authenticated attackers to execute arbitrary shell commands as the dokku system user by embedding shell metacharacters into git push operations.

Is CVE-2026-45408 being actively exploited?

No, CVE-2026-45408 is not listed in the CISA KEV catalog and no public exploits are currently known, but the low barrier to exploitation for authenticated users warrants immediate patching.

What versions of Docker are affected by CVE-2026-45408?

All versions of Docker/Dokku prior to 0.38.2 are affected by this vulnerability.

How do I check if my server is vulnerable to CVE-2026-45408?

Run 'dokku version' and verify the output is 0.38.2 or later. If earlier than 0.38.2, the system is vulnerable.

Does Defensia detect CVE-2026-45408?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Docker is installed on a monitored server, CVE-2026-45408 will appear in your dashboard with remediation steps.

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References

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