CVE-2025-66626

The patch deployed against CVE-2025-62156 is ineffective against malicious archives containing symbolic links.

Details

The untar code that handles symbolic links in archives is unsafe. Concretely, the computation of the link's target and the subsequent check are flawed:
https://github.com/argoproj/argo-workflows/blob/5291e0b01f94ba864f96f795bb500f2cfc5ad799/workflow/executor/executor.go#L1034-L1037

PoC

1. Create a malicious archive containing two files: a symbolik link with path "./work/foo" and target "/etc", and a normal text file with path "./work/foo/hostname".
2. Deploy a workflow like the one in https://github.com/argoproj/argo-workflows/security/advisories/GHSA-p84v-gxvw-73pf with the malicious archive mounted at /work/tmp.
3. Submit the workflow and wait for its execution.
4. Connect to the corresponding pod and observe that the file "/etc/hostname" was altered by the untar operation performed on the malicious archive. The attacker can hence alter arbitrary files in this way.

The attacker can overwrite the file /var/run/argo/argoexec with a script of their choice, which will be executed at the pod's start.

Untrusted input reaches a shell command, allowing arbitrary commands to run on the host. Typical impact: code execution in the application's environment.

CVE-2025-66626 has a CVSS score of 8.1 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.7.5, 3.6.14); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-66626? CVE-2025-66626 is a high-severity OS command injection vulnerability in github.com/argoproj/argo-workflows/v3 (go), affecting versions >= 3.7.0, < 3.7.5. It is fixed in 3.7.5, 3.6.14. Untrusted input reaches a shell command, allowing arbitrary commands to run on the host.
2. How severe is CVE-2025-66626? CVE-2025-66626 has a CVSS score of 8.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2025-66626?
   • github.com/argoproj/argo-workflows/v3 (go) (versions >= 3.7.0, < 3.7.5)
   • github.com/argoproj/argo-workflows (go) (versions <= 2.5.3-rc4)
4. Is there a fix for CVE-2025-66626? Yes. CVE-2025-66626 is fixed in 3.7.5, 3.6.14. Upgrade to this version or later.
5. Is CVE-2025-66626 exploitable, and should I be worried? Whether CVE-2025-66626 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-66626 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-66626?
   • Upgrade github.com/argoproj/argo-workflows/v3 to 3.7.5 or later
   • Upgrade github.com/argoproj/argo-workflows/v3 to 3.6.14 or later