HOMEVULNERABILITIESCVE-2020-5235
CRITICAL

CVE-2020-5235

CWE-125Published: February 4, 2020· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2020-5235 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

nanopb_project1 product(s)
nanopb
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/nanopb/nanopb/commit/45582f1f97f49e2abfdba1463d1e1027682d9856
PATCHhttps://github.com/nanopb/nanopb/commit/7b396821ddd06df8e39143f16e1dc0a4645b89a3
PATCHhttps://github.com/nanopb/nanopb/commit/aa9d0d1ca78d6adec3adfeecf3a706c7f9df81f2
PATCHhttps://github.com/nanopb/nanopb/security/advisories/GHSA-gcx3-7m76-287p
PATCHhttps://github.com/nanopb/nanopb/commit/45582f1f97f49e2abfdba1463d1e1027682d9856
PATCHhttps://github.com/nanopb/nanopb/commit/7b396821ddd06df8e39143f16e1dc0a4645b89a3
PATCHhttps://github.com/nanopb/nanopb/commit/aa9d0d1ca78d6adec3adfeecf3a706c7f9df81f2
PATCHhttps://github.com/nanopb/nanopb/security/advisories/GHSA-gcx3-7m76-287p

All References (8)

→
https://github.com/nanopb/nanopb/commit/45582f1f97f49e2abfdba1463d1e1027682d9856Patch · Third Party Advisory
→
https://github.com/nanopb/nanopb/commit/7b396821ddd06df8e39143f16e1dc0a4645b89a3Patch · Third Party Advisory
→
https://github.com/nanopb/nanopb/commit/aa9d0d1ca78d6adec3adfeecf3a706c7f9df81f2Patch · Third Party Advisory
→
https://github.com/nanopb/nanopb/security/advisories/GHSA-gcx3-7m76-287pPatch · Third Party Advisory
→
https://github.com/nanopb/nanopb/commit/45582f1f97f49e2abfdba1463d1e1027682d9856Patch · Third Party Advisory
→
https://github.com/nanopb/nanopb/commit/7b396821ddd06df8e39143f16e1dc0a4645b89a3Patch · Third Party Advisory
→
https://github.com/nanopb/nanopb/commit/aa9d0d1ca78d6adec3adfeecf3a706c7f9df81f2Patch · Third Party Advisory
→
https://github.com/nanopb/nanopb/security/advisories/GHSA-gcx3-7m76-287pPatch · Third Party Advisory

Quick Facts

CVE IDCVE-2020-5235
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-125
CISA KEVNo
Affected1 vendor(s)
PublishedFeb 4, 2020

Related CVEs (CWE-125)

CVE-2013-0767
10.0
CVE-2021-41556
10.0
CVE-2021-21777
10.0
CVE-2026-24826
10.0
CVE-2017-14451
10.0
CVE-2009-2523
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-5235 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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