CVE-2020-26243 Information

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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Reference

https://github.com/nanopb/nanopb/security/advisories/GHSA-85rr-4rh9-hhwh https://github.com/nanopb/nanopb/issues/615 https://github.com/nanopb/nanopb/blob/2b48a361786dfb1f63d229840217a93aae064667/CHANGELOG.txt https://github.com/nanopb/nanopb/commit/4fe23595732b6f1254cfc11a9b8d6da900b55b0c

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

7.5