How severe is CVE-2021-26461?

CVE-2021-26461 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-26461 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26461?

CVE-2021-26461 affects Apache Nuttx. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-26461?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-26461 published?

CVE-2021-26461 was published on 2021-06-21 and last updated on 2026-06-17.

CVE-2021-26461

CVE-2021-26461 is a critical-severity vulnerability in Apache Nuttx with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-190.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Apache Nuttx
Published: 2021-06-21
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2021-26461?: CVE-2021-26461 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-26461 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26461?: CVE-2021-26461 affects Apache Nuttx. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-26461?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-26461 published?: CVE-2021-26461 was published on 2021-06-21 and last updated on 2026-06-17.

References

https://lists.apache.org/thread.html/r806fccf8b003ae812d807c6c7d97950d44ed29b2713418cbe3f2bddd%40%3Cdev.nuttx.apache.org%3E

Affected products (1)

cpe:2.3:a:apache:nuttx:*:*:*:*:*:*:*:*

More vulnerabilities in Apache Nuttx

CVE-2025-47869 — Critical (CVSS 9.8): Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability was discovered in Apache NuttX…
CVE-2025-47868 — Critical (CVSS 9.8): Out-of-bounds Write resulting in possible Heap-based Buffer Overflow vulnerability was discovered in…
CVE-2025-35003 — Critical (CVSS 9.8): Improper Restriction of Operations within the Bounds of a Memory Buffer and Stack-based Buffer Overflow vulnerabilities…
CVE-2020-17529 — Critical (CVSS 9.8): Out-of-bounds Write vulnerability in TCP Stack of Apache NuttX (incubating) versions up to and including 9.1.0 and…
CVE-2020-1939 — Critical (CVSS 9.8): The Apache NuttX (Incubating) project provides an optional separate "apps" repository which contains various optional…
CVE-2020-17528 — Critical (CVSS 9.1): Out-of-bounds Write vulnerability in TCP stack of Apache NuttX (incubating) versions up to and including 9.1.0 and…

All CVEs affecting Apache Nuttx →

Other CWE-190 (Integer Overflow or Wraparound) vulnerabilities

CVE-2026-4689 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was…
CVE-2026-24814 — Critical (CVSS 10.0): Integer Overflow or Wraparound vulnerability in swoole swoole-src (thirdparty/hiredis modules). This vulnerability is…
CVE-2025-64721 — Critical (CVSS 10.0): Sandboxie is a sandbox-based isolation software for 32-bit and 64-bit Windows NT-based operating systems. In versions…
CVE-2015-5108 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
CVE-2015-5097 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
CVE-2013-2555 — Critical (CVSS 10.0): Integer overflow in Adobe Flash Player before 10.3.183.75 and 11.x before 11.7.700.169 on Windows and Mac OS X, before…

Browse all CWE-190 (Integer Overflow or Wraparound) vulnerabilities →