Vulnerability · Published Nov 25, 2020 · Assigned by GitHub_M
CVE-2020-26243Memory leak in nanopb
High 7.5
In plain English
A high-severity improper input validation in nanopb from nanopb. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.7% (higher than 86% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | nanopb | 0.4.4-1 | DEBIAN-CVE-2020-26243 |
| Debian:13 | nanopb | 0.4.4-1 | DEBIAN-CVE-2020-26243 |
| Debian:14 | nanopb | 0.4.4-1 | DEBIAN-CVE-2020-26243 |
| PyPI | nanopb | 0.3.9.7 | GHSA-85rr-4rh9-hhwh |
| PyPI | nanopb | 0.4.4 | GHSA-85rr-4rh9-hhwh |
| PyPI | nanopb | 0.3.9.7, 0.4.4 | PYSEC-2026-684 |
Affected products (as reported)
Weakness: CWE-20, CWE-119 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/nanopb/nanopb/security/advisories/GHSA-85rr-4rh9-hhwh x_refsource_CONFIRM
- https://github.com/nanopb/nanopb/issues/615 x_refsource_MISC
- https://github.com/nanopb/nanopb/commit/4fe23595732b6f1254cfc11a9b8d6da900b55b0c x_refsource_MISC
- https://github.com/nanopb/nanopb/blob/2b48a361786dfb1f63d229840217a93aae064667/CHANGELOG.txt x_refsource_MISC