Out-of-bounds Read in Nanopb

CVE-2020-5235

There is a potentially exploitable out of memory condition In Nanopb before 0.4.1, 0.3.9.5, and 0.2.9.4. When nanopb is compiled with PB_ENABLE_MALLOC, the message to be decoded contains a repeated string, bytes or message field and realloc() runs out of memory when expanding the array nanopb can end up calling `free()` on a pointer value that comes from uninitialized memory. Depending on platform this can result in a crash or further memory corruption, which may be exploitable in some cases. This problem is fixed in nanopb-0.4.1, nanopb-0.3.9.5, nanopb-0.2.9.4.

Vulnerability class: Buffer Overflow

EPSS: 0.017 (75.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:L.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2020-5235?
CVE-2020-5235 is a medium-severity vulnerability in Nanopb, classified under Out-of-bounds Read. CVSS score: 6.5/10. Published 2020-02-04.
How severe is CVE-2020-5235?
Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2020-5235 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.