CVE-2025-66626

HighPublic PoCRCE

Published: 09 December 2025

Published

09 December 2025

Modified

19 December 2025

KEV Added

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Patch

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CVSS Score 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

EPSS Score 0.0012 29.9th percentile

Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-66626 is a high-severity Relative Path Traversal (CWE-23) vulnerability in Argoproj Argo Workflows. Its CVSS base score is 8.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation of Remote Services (T1210); ranked at the 29.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation of Remote Services (T1210) and 2 other techniques. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Requires timely remediation of the specific flaw in Argo Workflows' untar code that mishandles symbolic link targets, preventing exploitation via patching to fixed versions 3.6.14 or 3.7.5.

SI-10 Information Input Validation good match

prevent

Mandates validation of information inputs such as tar archives to block malformed symbolic links enabling path traversal and arbitrary file overwrites outside intended directories.

SI-7 Software, Firmware, and Information Integrity partial match

preventdetect

Enforces integrity verification of critical files like /var/run/argo/argoexec to detect or prevent execution of overwritten malicious scripts at pod startup.

MITRE ATT&CK Enterprise TechniquesAI

T1210 Exploitation of Remote Services Lateral Movement

Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.

attack.mitre.org →

T1068 Exploitation for Privilege Escalation Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.

attack.mitre.org →

T1543.005 Container Service Persistence

Adversaries may create or modify container or container cluster management tools that run as daemons, agents, or services on individual hosts.

attack.mitre.org →

Why these techniques?

Vulnerability enables remote exploitation of Argo Workflows service via malicious tar archives with symlinks (T1210), allows low-priv Kubernetes users to achieve arbitrary code execution in pod context for potential priv esc (T1068), and facilitates overwriting argoexec script executed at pod startup (T1543.005).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

NVD Description

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. Versions 3.6.13 and below and versions 3.7.0 through 3.7.4, contain unsafe untar code that handles symbolic links in archives. Concretely, the computation of a link's…

target and the subsequent check are flawed. An attacker can overwrite the file /var/run/argo/argoexec with a script of their choice, which would be executed at the pod's start. The patch deployed against CVE-2025-62156 is ineffective against malicious archives containing symbolic links. This issue is fixed in versions 3.6.14 and 3.7.5.

Deeper analysisAI

CVE-2025-66626 is a vulnerability in Argo Workflows, an open-source container-native workflow engine for orchestrating parallel jobs on Kubernetes. It affects versions 3.6.13 and below, as well as versions 3.7.0 through 3.7.4, due to unsafe untar code that mishandles symbolic links in archives. Specifically, the computation of a symbolic link's target and the subsequent security check are flawed, enabling file overwrites outside intended directories. The issue carries a CVSS v3.1 base score of 8.1 (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H) and maps to CWEs-23 (Relative Path Traversal), CWE-78 (OS Command Injection), and CWE-59 (Symbolic Link Following).

An attacker requires low privileges (PR:L), such as those of an authenticated Kubernetes user able to submit workflows, and network access to the Argo server. By supplying a malicious archive containing symbolic links during workflow execution, they can overwrite the file /var/run/argo/argoexec with a custom script. This script executes automatically at the pod's startup, granting high-impact integrity and availability disruption, such as arbitrary code execution within the pod's context.

GitHub Security Advisories (GHSA-p84v-gxvw-73pf and GHSA-xrqc-7xgx-c9vh) confirm the vulnerability and note that the patch for the related CVE-2025-62156 fails against symbolic link attacks. Mitigation requires upgrading to Argo Workflows versions 3.6.14 or 3.7.5, where the fix addresses the flawed link target computation in executor.go (lines 1034-1037) via commit 6b92af23f35aed4d4de8b04adcaf19d68f006de1.