Impact "nextflow auth login" persists Seqera Platform OIDC tokens to "${NXF_HOME:-~/.nextflow}/seqera-auth.config". The file is created via Java NIO without specifying file permissions, so under the default "umask 022" it lands at mode "0644" (world-readable). On a multi-user POSIX host — typically an HPC login node, shared workstation, or jump host — any local user able to traverse the victim's home directory can read the file and obtain a valid Platform bearer token, enabling impersonation against Seqera Platform within the token's scope. Single-user systems and headless CI runners, which do not invoke the interactive login flow, are not affected. Affected versions: "25.09.2-edge" through "26.04.1". Patches Fixed in "<PATCHED_VERSION>". The patched code applies mode "0600" to "seqera-auth.config" immediately after writing it, and re-applies on every subsequent login so any pre-existing world-readable copy left by an earlier version is tightened. Tokens previously stored in the file must be treated as disclosed. After upgrading, run "nextflow auth logout", revoke the token in the Seqera Platform UI, and run "nextflow auth login" again. Workarounds Restrict the file and its parent directory: "chmod 600 "${NXF_HOME:-$HOME/.nextflow}/seqera-auth.config"" "chmod 700 "${NXF_HOME:-$HOME/.nextflow}"" Alternatively, supply the Platform token via the "TOWER_ACCESS_TOKEN" environment variable instead of running "nextflow auth login". References - https://cwe.mitre.org/data/definitions/276.html