What is CVE-2021-26461?

CVE-2021-26461 is a critical-severity vulnerability in Apache Nuttx, classified under Integer Overflow or Wraparound. CVSS score: 9.8/10. Published 2021-06-21.

How severe is CVE-2021-26461?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Integer overflow in Apache Nuttx

CVE-2021-26461

Apache Nuttx Versions prior to 10.1.0 are vulnerable to integer wrap-around in functions malloc, realloc and memalign. This improper memory assignment can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or a remote code injection/execution.

Vulnerability class: Integer Overflow

Published 2021-06-21 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.050 (92.0th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 92nd percentile — 92.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.050 · newest: 0.050 · change: 0.000

Affected products

Apache Nuttx
Apache Software Foundation Nuttx — versions Apache NuttX

Weakness classification (CWE)

CWE-190 — Integer Overflow or Wraparound

References

lists.apache.org/thread.html/r806fccf8b003ae812d807c6c7d97950d44ed29b2713418cbe… (Mailing List, Vendor Advisory)

Frequently asked questions

What is CVE-2021-26461?: CVE-2021-26461 is a critical-severity vulnerability in Apache Nuttx, classified under Integer Overflow or Wraparound. CVSS score: 9.8/10. Published 2021-06-21.
How severe is CVE-2021-26461?: Critical severity. CVSS v3 base score is 9.8 out of 10.