QID 983222

QID 983222: Python (pip) Security Update for nanopb (GHSA-85rr-4rh9-hhwh)

Security update has been released for nanopb to fix the vulnerability.

Note: The preceding description block is extracted directly from the security advisory. Using automation, we have attempted to clean and format it as much as possible without introducing additional issues.

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.

CVSS V3 rated as High - 7.5 severity.

CVSS V2 rated as Medium - 4.3 severity.

Solution

Preliminary patch is [available on git](https://github.com/nanopb/nanopb/commit/edf6dcbffee4d614ac0c2c1b258ab95185bdb6e9) and problem will be patched in versions 0.3.9.7 and 0.4.4 once testing has been completed.Workaround:
Following workarounds are available:
* 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.
* 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.
* Use an arena allocator for nanopb, to make sure all memory can be released afterwards.

Vendor References

GHSA-85rr-4rh9-hhwh - github.com/advisories/GHSA-85rr-4rh9-hhwh

CVEs related to QID 983222

CVE-2020-26243 |

Software Advisories

Advisory ID	Software	Component	Link
GHSA-85rr-4rh9-hhwh	nanopb		github.com/advisories/GHSA-85rr-4rh9-hhwh

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