CVE-2021-21401

Public Exploit
Invalid free() call in Nanopb

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.

Category

7.1
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.20%
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-2021-21401?
CVE-2021-21401 has been scored as a high severity vulnerability.
How to fix CVE-2021-21401?
To fix CVE-2021-21401, 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-2021-21401 being actively exploited in the wild?
It is possible that CVE-2021-21401 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-2021-21401?
CVE-2021-21401 affects nanopb nanopb.
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