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CVE-2020-26243PYSEC-2026-684GHSA-85RR-4RH9-HHWH

Memory leak in nanopb

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 0.3.9.7, 0.4.4
None on Exploit-DB, Metasploit or GitHub

Summary

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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • nanopb nanopb

    fixed in 0.3.9.7; From 0.4.0 · fixed in 0.4.4

  • nanopbPyPI

    From 0.3.2 · fixed in 0.3.9.7; From 0.4.0 · fixed in 0.4.4

  • nanopbPyPI

    From 0.3.2 · fixed in 0.3.9.7

  • nanopbPyPI

    From 0.4.0 · fixed in 0.4.4

References 4

GitHub · nanopb/nanopb