CVE-2020-26243

Public Exploit
Memory leak in nanopb

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.

Category

7.5
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.11%
Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory github.com
Affected: nanopb nanopb
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2020-26243?
CVE-2020-26243 has been scored as a high severity vulnerability.
How to fix CVE-2020-26243?
To fix CVE-2020-26243, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2020-26243 being actively exploited in the wild?
It is possible that CVE-2020-26243 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2020-26243?
CVE-2020-26243 affects nanopb nanopb.
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