RCE via ZipSlip and symbolic links in argoproj/argo-workflows

High8.1CVE-2025-66626 · Published Dec 9, 2025 · updated Sep 10, 2026

### Summary 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. ### Impact 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.