TI-2020-16064 Aliases CVE-2020-26243 GHSA-85rr-4rh9-hhwh

Memory leak in nanopb

LOW 38CWE-119Published 2020-11-25 · Updated 2024-08-04

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-119 and the CVSS impact.

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.

Why it matters now

EPSS 0.02664 85th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Partial nanopb (nanopb): 0.3.9.7, 0.4.4nanopb (PyPI): 0.3.9.7, 0.4.4Red Hat: 1 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
nanopb	nanopb	before 0.3.9.7; 0.4.0 to before 0.4.4	0.3.9.7, 0.4.4	Patch available	CNA
—	nanopb (PyPI)	0.3.2 to before 0.3.9.7	0.3.9.7	Patch available	GHSA-85rr-4rh9-hhwh
—	nanopb (PyPI)	0.4.0 to before 0.4.4	0.4.4	Patch available	GHSA-85rr-4rh9-hhwh

nanopb Vendornanopb Affected before 0.3.9.7; 0.4.0 to before 0.4.4 Fixed in 0.3.9.7, 0.4.4 Patch available CNA
nanopb (PyPI) Vendor— Affected 0.3.2 to before 0.3.9.7 Fixed in 0.3.9.7 Patch available GHSA-85rr-4rh9-hhwh
nanopb (PyPI) Vendor— Affected 0.4.0 to before 0.4.4 Fixed in 0.4.4 Patch available GHSA-85rr-4rh9-hhwh

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:nanopb_project:nanopb::::::::	before 0.3.9.7; 0.4.0 to before 0.4.4	Vulnerable	nanopb

cpe:2.3:a:nanopb_project:nanopb:*:*:*:*:*:*:*:* Versions before 0.3.9.7; 0.4.0 to before 0.4.4 Vulnerable ·nanopb

Remediation

Fix · CNA nanopb (nanopb) Fixed in 0.3.9.7, 0.4.4
Fix · GHSA-85rr-4rh9-hhwh nanopb (PyPI) Fixed in 0.3.9.7 Advisory →
Fix · GHSA-85rr-4rh9-hhwh nanopb (PyPI) Fixed in 0.4.4 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
OpenShift Service Mesh 1	Affected	No fix planned: Will not fix

Timeline

2026-10-02 Threatist record created from CVE-2020-26243
2026-10-03 Alias added: GHSA-85rr-4rh9-hhwh

References

Exploit 1

https://github.com/nanopb/nanopb/issues/615

Patch 1

https://github.com/nanopb/nanopb/commit/4fe23595732b6f1254cfc11a9b8d6da900b55b0c

Advisory 3

TI-2014-08406 Nanopb before 0.3.1 allows size_t overflows in pb_dec_bytes and pb_dec_string. CVSS 3.1CRITICAL 9.8
TI-2020-04291 Out-of-memory condition in Nanopb is potentially exploitable CVSS 3.1CRITICAL 9.8
TI-2021-04499 Invalid free() call in Nanopb CVSS 3.1HIGH 7.1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences