CVE-2020-5235

Advisory

Nanopb 0.4.1, 0.3.9.5 and 0.2.9.4 include a fix for CVE-2020-5235: There is a potentially exploitable out of memory condition In Nanopb before 0.4.1, 0.3.9.5, and 0.2.9.4. When nanopb is compiled with PB_ENABLE_MALLOC, the message to be decoded contains a repeated string, bytes or message field and realloc() runs out of memory when expanding the array nanopb can end up calling `free()` on a pointer value that comes from uninitialized memory. Depending on platform this can result in a crash or further memory corruption, which may be exploitable in some cases.
https://github.com/nanopb/nanopb/security/advisories/GHSA-gcx3-7m76-287p

Affected package

Affected versions

Fixed versions

Vulnerability changelog

Fix invalid free() after failed realloc() (GHSA-gcx3-7m76-287p)
Avoid overflows in allocation for packed fields.
Verify stream size before allocating string / bytes.
Add workaround for avr-libc realloc() bug (475)
Fix bug with field numbers >255 (407)
Fix compilation error on platforms without uint8_t (485)
Fix warnings on Python3.8 (399, 467)
Make fixed_count option work when combined with FT_POINTER.
Add missing define for submsg callbacks, add regression test (472)
Fix ImportError when using generator/protoc with Python 3
Remove accidental debug code in generator
Reduce stack usage (484)
Remove PB_FIELDINFO_WIDTH option (473)
Add nanopb-specific package name option (422)
Add testcase for Any type (163)
Add exclude option also from .proto/.options
Set default include path in the grpc_tools protoc wrapper.
Add workaround for python-protobuf 3.6.1 bug (478)
Detect invalid wire type when decoding fields.
Improved fuzz testing

Resources

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-5235
• https://github.com/nanopb/nanopb/commit/45582f1f97f49e2abfdba1463d1e1027682d9856
• https://github.com/nanopb/nanopb/commit/7b396821ddd06df8e39143f16e1dc0a4645b89a3
• https://github.com/nanopb/nanopb/security/advisories/GHSA-gcx3-7m76-287p
• https://github.com/nanopb/nanopb/commit/aa9d0d1ca78d6adec3adfeecf3a706c7f9df81f2