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Vulnerability · Published Mar 23, 2021 · Assigned by GitHub_M

CVE-2021-21401Invalid free() call in Nanopb

High 7.1

In plain English

A high-severity security flaw 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 1.8% (higher than 79% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.1High
Exploit odds (30 days)1.8%top 21.3% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack tooling1Public PoC

Official description

Nanopb is a small code-size Protocol Buffers implementation in ansi C. In Nanopb before versions 0.3.9.8 and 0.4.5, decoding a specifically formed message can cause invalid `free()` or `realloc()` calls if the message type contains an `oneof` field, and the `oneof` directly contains both a pointer field and a non-pointer field. If the message data first contains the non-pointer field and then the pointer field, the data of the non-pointer field is incorrectly treated as if it was a pointer value. Such message data rarely occurs in normal messages, but it is a concern when untrusted data is parsed. This has been fixed in versions 0.3.9.8 and 0.4.5. See referenced GitHub Security Advisory for more information including workarounds.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12nanopb0.4.4-2DEBIAN-CVE-2021-21401
Debian:13nanopb0.4.4-2DEBIAN-CVE-2021-21401
Debian:14nanopb0.4.4-2DEBIAN-CVE-2021-21401
PyPInanopb0.3.9.8GHSA-7mv5-5mxh-qg88
PyPInanopb0.4.5GHSA-7mv5-5mxh-qg88
PyPInanopb0.3.9.8, 0.4.5PYSEC-2021-432

Affected products (as reported)

VendorProductVersions
nanopb nanopb >= 0.3.2, <= 0.3.9.7>= 0.4.0, <= 0.4.4

Weakness: CWE-763 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L

References