CVE catalog
CVE-2020-26243
nanopb: CVE-2020-26243
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 2.66% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | nanopb | sid | 0.4.9.1-2 | fixed |
| Debian | nanopb | forky | 0.4.9.1-2 | fixed |
| Debian | nanopb | trixie | 0.4.9.1-1 | fixed |
| Debian | nanopb | bookworm | 0.4.7-2 | fixed |
| Ubuntu | nanopb | pro | 0.4.1-1 | vulnerable |
| Ubuntu | nanopb | pro | 0.4.1-1ubuntu0.1~esm1 | fixed |
| Ubuntu | nanopb | pro | 0.4.1-1 | vulnerable |
| Ubuntu | nanopb | pro | 0.4.1-1ubuntu0.1~esm1 | fixed |
| Opensuse | nanopb | tumbleweed | 0.4.5-1.3 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | nanopb | source | sid | 0.4.4-1 | not yet assigned | Not reported | [975838] |
| Debian | nanopb | source | forky | 0.4.4-1 | not yet assigned | Not reported | [975838] |
| Debian | nanopb | source | trixie | 0.4.4-1 | not yet assigned | Not reported | [975838] |
| Debian | nanopb | source | bookworm | 0.4.4-1 | not yet assigned | Not reported | [975838] |
| Ubuntu | nanopb | deb | pro | 0.4.1-1ubuntu0.1~esm1 | Not reported | UBUNTU-CVE-2020-26243 | Not reported |
| Ubuntu | nanopb | deb | pro | 0.4.1-1ubuntu0.1~esm1 | Not reported | USN-6121-1 | Not reported |
| Opensuse | nanopb | rpm | tumbleweed | 0.4.5-1.3 | Not reported | OPENSUSE-SU-2024:11074-1 | Not reported |
OpenFactory catalog packages
[openSUSE Tumbleweed]
- [libprotobuf-nanopb0]Unknown
Source package: [nanopb]
Details (1)
0.4.9.1-1.8· x86_64 · tumbleweedUnknown · Fixed:
0.4.5-1.3Version impact unknown
dsa · nanopb · opensuse · tumbleweed
- [nanopb-devel]Unknown
Source package: [nanopb]
Details (1)
0.4.9.1-1.8· x86_64 · tumbleweedUnknown · Fixed:
0.4.5-1.3Version impact unknown
dsa · nanopb · opensuse · tumbleweed
- [nanopb-source]Unknown
Source package: [nanopb]
Details (1)
0.4.9.1-1.8· noarch · tumbleweedUnknown · Fixed:
0.4.5-1.3Version impact unknown
dsa · nanopb · opensuse · tumbleweed
[Debian 12 (Bookworm)]
- [libnanopb-dev]Fixed
Source package: [nanopb]
Details (2)
0.4.7-2· amd64 · bookwormFixed · Fixed:
0.4.4-1dsa · nanopb · debian · bookworm; dsa · nanopb · debian · 12
0.4.7-2· arm64 · bookwormFixed · Fixed:
0.4.4-1dsa · nanopb · debian · bookworm; dsa · nanopb · debian · 12
- [nanopb]Fixed
Details (2)
0.4.7-2· all · bookwormFixed · Fixed:
0.4.4-1dsa · nanopb · debian · bookworm; dsa · nanopb · debian · 12
0.4.7-2· all · bookwormFixed · Fixed:
0.4.4-1dsa · nanopb · debian · bookworm; dsa · nanopb · debian · 12
[Debian 13 (Trixie)]
- [libnanopb-dev]Fixed
Source package: [nanopb]
Details (2)
0.4.9.1-1· amd64 · trixieFixed · Fixed:
0.4.4-1dsa · nanopb · debian · 13
0.4.9.1-1· arm64 · trixieFixed · Fixed:
0.4.4-1dsa · nanopb · debian · 13
- [nanopb]Fixed
Details (2)
0.4.9.1-1· all · trixieFixed · Fixed:
0.4.4-1dsa · nanopb · debian · 13
0.4.9.1-1· all · trixieFixed · Fixed:
0.4.4-1dsa · nanopb · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2024_11074-1.json]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2020-26243]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2020-26243]
- [https://osv.dev/vulnerability/USN-6121-1]
- [https://osv.dev/vulnerability/openSUSE-SU-2024:11074-1]
- [https://security-tracker.debian.org/tracker/CVE-2020-26243]
- [https://security.access.redhat.com/data/csaf/v2/vex/2020/cve-2020-26243.json]
[Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]