How severe is CVE-2026-51540?

CVE-2026-51540 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-2026-51540 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-51540?

CVE-2026-51540 affects Opener Project Opener. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-51540?

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-2026-51540 published?

CVE-2026-51540 was published on 2026-07-13 and last updated on 2026-08-11.

CVE-2026-51540

CVE-2026-51540 is a critical-severity vulnerability in Opener Project Opener 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-191.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-191
Affected product: Opener Project Opener
Published: 2026-07-13
Last modified: 2026-08-11

Description

OpENer 2.3.0 (master branch up to commit 76b95cf) is vulnerable to a severe memory corruption issue caused by an integer underflow in the processing of connected explicit messages (SendUnitData).

Frequently asked questions

What is CVE-2026-51540?: OpENer 2.3.0 (master branch up to commit 76b95cf) is vulnerable to a severe memory corruption issue caused by an integer underflow in the processing of connected explicit messages (SendUnitData).
How severe is CVE-2026-51540?: CVE-2026-51540 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-2026-51540 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-51540?: CVE-2026-51540 affects Opener Project Opener. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-51540?: 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-2026-51540 published?: CVE-2026-51540 was published on 2026-07-13 and last updated on 2026-08-11.

References

Affected products (1)

cpe:2.3:a:opener_project:opener:2.3.0:*:*:*:*:*:*:*

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