How severe is CVE-2026-26399?

CVE-2026-26399 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-26399 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-26399?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-26399 have an EU (EUVD) identifier?

Yes. CVE-2026-26399 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23912.

When was CVE-2026-26399 published?

CVE-2026-26399 was published on 2026-04-20 and last updated on 2026-06-17.

CVE-2026-26399

CVE-2026-26399 is a medium-severity vulnerability with a CVSS 3.x base score of 5.3. 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-562.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (8th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-23912
Weakness: CWE-562
Published: 2026-04-20
Last modified: 2026-06-17

Description

A stack-use-after-return issue exists in the Arduino_Core_STM32 library prior to version 1.7.0. The pwm_start() function allocates a TIM_HandleTypeDef structure on the stack and passes its address to HAL initialization routines, where it is stored in a global timer handle registry. After the function returns, interrupt service routines may dereference this dangling pointer, resulting in memory corruption.

Frequently asked questions

What is CVE-2026-26399?: A stack-use-after-return issue exists in the Arduino_Core_STM32 library prior to version 1.7.0. The pwm_start() function allocates a TIM_HandleTypeDef structure on the stack and passes its address to HAL initialization routines, where it is stored in a global timer handle registry. After the function returns, interrupt service routines may dereference this dangling pointer, resulting in memory corruption.
How severe is CVE-2026-26399?: CVE-2026-26399 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-26399 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-26399?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-26399 have an EU (EUVD) identifier?: Yes. CVE-2026-26399 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23912.
When was CVE-2026-26399 published?: CVE-2026-26399 was published on 2026-04-20 and last updated on 2026-06-17.

References

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