b2-sdk-python TOCTOU application key disclosure
Impact
Linux and Mac releases of the SDK version 1.14.0 and below contain a key disclosure vulnerability that, in certain conditions, can be exploited by local attackers through a time-of-check-time-of-use (TOCTOU) race condition.
SDK users of the SqliteAccountInfo format are vulnerable while users of the InMemoryAccountInfo format are safe. The SqliteAccountInfo saves API keys (and bucket name-to-id mapping) in a local database file ($XDG_CONFIG_HOME/b2/account_info, ~/.b2_account_info or a user-defined path). When first created, the file is world readable and is (typically a few milliseconds) later altered to be private to the user. If the directory containing the file is readable by a local attacker then during the brief period between file creation and permission modification, a local attacker can race to open the file and maintain a handle to it. This allows the local attacker to read the contents after the file after the sensitive information has been saved to it.
Consumers of this SDK who rely on it to save data using SqliteAccountInfo class should upgrade to the latest version of the SDK. Those who believe a local user might have opened a handle using this race condition, should remove the affected database files and regenerate all application keys.
Patches
Users should upgrade to b2-sdk-python 1.14.1 or later.
For more information
See the related advisory in the B2 Command Line Tool, a consumer of this SDK.
If you have any questions or comments about this advisory:
- Open an issue in b2-sdk-python
- Email us at security@backblaze.com
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | b2sdk | < 1.14.1 | 1.14.1 |
References
- https://github.com/Backblaze/b2-sdk-python/commit/62476638986e5b6d7459aca5ef8ce220760226e0
- https://pypi.org/project/b2sdk/
- https://github.com/Backblaze/b2-sdk-python/security/advisories/GHSA-p867-fxfr-ph2w
- https://nvd.nist.gov/vuln/detail/CVE-2022-23651
- https://github.com/Backblaze/b2-sdk-python
- https://github.com/pypa/advisory-database/tree/main/vulns/b2sdk/PYSEC-2022-33.yaml
- https://pypi.org/project/b2sdk
- CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N- Weakness (CWE)
CWE-367- Platform
- Python (PyPI)
- Package
b2sdk- Disclosed
- 23.02.2022
- Updated
- 11.10.2026 11:19
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2022-33 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-p867-fxfr-ph2w - CC BY 4.0
Vulnerability history: b2sdk
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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