요약
- CVE-2020-26243은(는) nanopb, nanopb (nanopb project)에 영향을 주는 높음 (CVSS 7.5) 취약점입니다.
- 향후 30일 내 악용 확률(EPSS): 2.7%, 전체 취약점의 85.8%보다 높음.
- 조치: 0.3.9.7, 0.4.4 이상으로 업데이트하세요.
| Package | Affected versions | Patched versions |
|---|
| nanopb PyPI | ≥ 0.3.2, < 0.3.9.7≥ 0.4.0, < 0.4.4
| 0.3.9.70.4.4
|
| nanopb | ≥ 0.4.0, < 0.4.4< 0.3.9.7
| 0.4.40.3.9.7
|
Description
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_unions for 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.
NVD description
Nanopb is a small code-size Protocol Buffers implementation. In Nanopb before versions 0.4.4 and 0.3.9.7, 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. This is fixed in versions 0.3.9.7 and 0.4.4. The following workarounds are available: 1) Set the option `no_unions` for the oneof field. This will generate fields as separate instead of C union, and avoids triggering the problematic code. 2) 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. 3) Use an arena allocator for nanopb, to make sure all memory can be released afterwards.
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