Pi auth.json writes could briefly expose stored credentials to local users
Pi stored API keys and OAuth credentials in auth.json. A race condition in the file write path could briefly create or rewrite this file with permissions derived from the process umask before tightening the file to owner-only permissions.
Info
The affected credential storage code wrote auth.json and then corrected the file mode in a separate operation. During the interval between those operations, a local user who could read and traverse the Pi agent configuration directory could potentially read the file before its permissions were restricted.
The file can contain API keys, OAuth access tokens, and OAuth refresh tokens for configured providers. The affected behavior was present in the original auth.json credential storage implementation and thus affects both the original @mariozechner/pi-coding-agent package as well as @earendil-works/pi-coding-agent.
Impact
Exploitation requires local access to the same machine and read/traverse access to the victim's Pi agent configuration directory. Users whose ~/.pi/agent directory is private to their account are less exposed. The main impact is disclosure of stored provider credentials, which may allow use of the configured provider accounts according to the privileges of those credentials.
This is not remotely exploitable by itself.
Affected versions
- Affected:
@mariozechner/pi-coding-agent >= 0.28.0, <= 0.73.1
- Affected:
@earendil-works/pi-coding-agent >= 0.74.0, < 0.78.1
- Patched:
@earendil-works/pi-coding-agent >= 0.78.1
The solution
Version 0.78.1 changed the credential storage writes to create auth.json with mode 0600 at open time. The fix applies to initial file creation and credential save paths, including OAuth token refresh writes.
Recommendations
Upgrade to @earendil-works/pi-coding-agent version 0.78.1 or later. Users still on the deprecated @mariozechner/pi-coding-agent package should migrate to the @earendil-works/pi-coding-agent package and install version 0.78.1 or later.
After upgrading, rotate any credentials that may have been exposed on multi-user systems where the Pi agent configuration directory was readable by other local users.
Workarounds
If upgrading immediately is not possible, restrict the Pi agent configuration directory so only the owning user can traverse it, restrict auth.json to owner-only permissions, and run Pi with a restrictive umask such as 077 until the upgrade is complete.
Timeline
- 2026-05-29: Report received
- 2026-06-02: Fix committed
- 2026-06-04: Fixed version released
- 2026-06-08: Advisory published
Credits
Reported by Paul Urian and Cosmin Alexa of CrowdStrike.
References
urianpaul94 Reporter
Pi auth.json writes could briefly expose stored credentials to local users
Pi stored API keys and OAuth credentials in
auth.json. A race condition in the file write path could briefly create or rewrite this file with permissions derived from the process umask before tightening the file to owner-only permissions.Info
The affected credential storage code wrote
auth.jsonand then corrected the file mode in a separate operation. During the interval between those operations, a local user who could read and traverse the Pi agent configuration directory could potentially read the file before its permissions were restricted.The file can contain API keys, OAuth access tokens, and OAuth refresh tokens for configured providers. The affected behavior was present in the original
auth.jsoncredential storage implementation and thus affects both the original@mariozechner/pi-coding-agentpackage as well as@earendil-works/pi-coding-agent.Impact
Exploitation requires local access to the same machine and read/traverse access to the victim's Pi agent configuration directory. Users whose
~/.pi/agentdirectory is private to their account are less exposed. The main impact is disclosure of stored provider credentials, which may allow use of the configured provider accounts according to the privileges of those credentials.This is not remotely exploitable by itself.
Affected versions
@mariozechner/pi-coding-agent >= 0.28.0, <= 0.73.1@earendil-works/pi-coding-agent >= 0.74.0, < 0.78.1@earendil-works/pi-coding-agent >= 0.78.1The solution
Version 0.78.1 changed the credential storage writes to create
auth.jsonwith mode0600at open time. The fix applies to initial file creation and credential save paths, including OAuth token refresh writes.Recommendations
Upgrade to
@earendil-works/pi-coding-agentversion 0.78.1 or later. Users still on the deprecated@mariozechner/pi-coding-agentpackage should migrate to the@earendil-works/pi-coding-agentpackage and install version 0.78.1 or later.After upgrading, rotate any credentials that may have been exposed on multi-user systems where the Pi agent configuration directory was readable by other local users.
Workarounds
If upgrading immediately is not possible, restrict the Pi agent configuration directory so only the owning user can traverse it, restrict
auth.jsonto owner-only permissions, and run Pi with a restrictive umask such as077until the upgrade is complete.Timeline
Credits
Reported by Paul Urian and Cosmin Alexa of CrowdStrike.
References