Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nanopb Project | Nanopb | < 0.3.9.7 |
Related Weaknesses (CWE)
References
- https://github.com/nanopb/nanopb/blob/2b48a361786dfb1f63d229840217a93aae064667/CRelease NotesThird Party Advisory
- https://github.com/nanopb/nanopb/commit/4fe23595732b6f1254cfc11a9b8d6da900b55b0cPatchThird Party Advisory
- https://github.com/nanopb/nanopb/issues/615ExploitPatchThird Party Advisory
- https://github.com/nanopb/nanopb/security/advisories/GHSA-85rr-4rh9-hhwhThird Party Advisory
- https://github.com/nanopb/nanopb/blob/2b48a361786dfb1f63d229840217a93aae064667/CRelease NotesThird Party Advisory
- https://github.com/nanopb/nanopb/commit/4fe23595732b6f1254cfc11a9b8d6da900b55b0cPatchThird Party Advisory
- https://github.com/nanopb/nanopb/issues/615ExploitPatchThird Party Advisory
- https://github.com/nanopb/nanopb/security/advisories/GHSA-85rr-4rh9-hhwhThird Party Advisory
FAQ
What is CVE-2020-26243?
CVE-2020-26243 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 o...
How severe is CVE-2020-26243?
CVE-2020-26243 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2020-26243?
Check the references section above for vendor advisories and patch information. Affected products include: Nanopb Project Nanopb.