protobuf affected by a JSON recursion depth bypass
A denial-of-service (DoS) vulnerability exists in google.protobuf.json_format.ParseDict() in Python, where the max_recursion_depth limit can be bypassed when parsing nested google.protobuf.Any messages.
Due to missing recursion depth accounting inside the internal Any-handling logic, an attacker can supply deeply nested Any structures that bypass the intended recursion limit, eventually exhausting Python’s recursion stack and causing a RecursionError.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | protobuf | >= 6.30.0rc1, < 6.33.5, < 5.29.6 | 6.33.5, 5.29.6 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-0994
- https://github.com/protocolbuffers/protobuf/issues/25070
- https://github.com/protocolbuffers/protobuf/pull/25239
- https://github.com/protocolbuffers/protobuf/commit/5ebddcb1bcbe51d1fe323baa145e85f4f23128cf
- https://github.com/protocolbuffers/protobuf/commit/d2b001626d137c62dfee6c88c87324102531868b
- https://github.com/protocolbuffers/protobuf
- https://pypi.org/project/protobuf
- https://github.com/advisories/GHSA-7gcm-g887-7qv7
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L- Weakness (CWE)
CWE-674- Platform
- Python (PyPI)
- Package
protobuf- Disclosed
- 23.01.2026
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-1805 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-7gcm-g887-7qv7 - CC BY 4.0
Vulnerability history: protobuf
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 5
- First → latest
- 09.2017 01.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 5
Disclosures per year
- 2017: 1
- 2018: 0
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 2
- 2023: 0
- 2024: 0
- 2025: 1
- 2026: 1
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protobuf affected by a JSON recursion depth bypass this entry
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