Memory leak in Nanopb
Impact
Decoding specifically formed message can leak memory if dynamic allocation is enabled and an oneof field contains a static submessage that contains a dynamic field, and the message being decoded contains the submessage multiple times. This is rare in normal messages, but it is a concern when untrusted data is parsed.
Patches
Preliminary patch is available on git and problem will be patched in versions 0.3.9.7 and 0.4.4 once testing has been completed.
Workarounds
Following workarounds are available:
- Set the option
no_unionsfor the oneof field. This will generate fields as separate instead of C union, and avoids triggering the problematic code. - Set the type of the submessage field inside oneof to
FT_POINTER. This way the whole submessage will be dynamically allocated and the problematic code is not executed. - Use an arena allocator for nanopb, to make sure all memory can be released afterwards.
References
Bug report: https://github.com/nanopb/nanopb/issues/615
For more information
If you have any questions or comments about this advisory, comment on the bug report linked above.
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | nanopb | >= 0.3.2, < 0.3.9.7, >= 0.4.0, < 0.4.4 | 0.3.9.7, 0.4.4 |
Referencias
- https://github.com/nanopb/nanopb/security/advisories/GHSA-85rr-4rh9-hhwh
- https://nvd.nist.gov/vuln/detail/CVE-2020-26243
- https://github.com/nanopb/nanopb/issues/615
- https://github.com/nanopb/nanopb/commit/4fe23595732b6f1254cfc11a9b8d6da900b55b0c
- https://github.com/nanopb/nanopb/blob/2b48a361786dfb1f63d229840217a93aae064667/CHANGELOG.txt
- https://pypi.org/project/nanopb
- https://github.com/advisories/GHSA-85rr-4rh9-hhwh
- Vector CVSS
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Debilidad (CWE)
CWE-119, CWE-20- Plataforma
- Python (PyPI)
- Paquete
nanopb- Publicada
- 25.11.2020
- Actualizado
- 11.10.2026 13:19
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2026-684 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-85rr-4rh9-hhwh - CC BY 4.0
Historial de vulnerabilidades: nanopb
Todas las vulnerabilidades publicadas de este paquete (Python (PyPI)), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 2
- Primera → última
- 11.2020 03.2021
- Sin corrección
- 0
- Explotada en ataques
- 0
Distribución por gravedad
- Alta 1
- Media 1
Divulgaciones por año
- 2020: 1
- 2021: 1
- 2022: 0
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 0
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Memory leak in Nanopb esta entrada
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