How severe is CVE-2026-33396?

CVE-2026-33396 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-33396 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-33396?

CVE-2026-33396 affects Hackerbay Oneuptime. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-33396?

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.

Does CVE-2026-33396 have an EU (EUVD) identifier?

Yes. CVE-2026-33396 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-16189.

When was CVE-2026-33396 published?

CVE-2026-33396 was published on 2026-03-26 and last updated on 2026-06-17.

CVE-2026-33396

CVE-2026-33396 is a critical-severity vulnerability in Hackerbay Oneuptime with a CVSS 3.x base score of 9.9. 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-78.

Key facts

Severity: Critical (CVSS 3.x base score 9.9)
EPSS exploit prediction: 1% (55th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-16189
Weakness: CWE-78
Affected product: Hackerbay Oneuptime
Published: 2026-03-26
Last modified: 2026-06-17

Description

OneUptime is an open-source monitoring and observability platform. Prior to version 10.0.35, a low-privileged authenticated user (ProjectMember) can achieve remote command execution on the Probe container/host by abusing Synthetic Monitor Playwright script execution. Synthetic monitor code is executed in VMRunner.runCodeInNodeVM with a live Playwright page object in context. The sandbox relies on a denylist of blocked properties/methods, but it is incomplete. Specifically, _browserType and launchServer are not blocked, so attacker code can traverse `page.context().browser()._browserType.launchServer(...)` and spawn arbitrary processes. Version 10.0.35 contains a patch.

Frequently asked questions

What is CVE-2026-33396?: OneUptime is an open-source monitoring and observability platform. Prior to version 10.0.35, a low-privileged authenticated user (ProjectMember) can achieve remote command execution on the Probe container/host by abusing Synthetic Monitor Playwright script execution. Synthetic monitor code is executed in VMRunner.runCodeInNodeVM with a live Playwright page object in context. The sandbox relies on a denylist of blocked properties/methods, but it is incomplete. Specifically, _browserType and launchServer are not blocked, so attacker code can traverse `page.context().browser()._browserType.launchServer(...)` and spawn arbitrary processes. Version 10.0.35 contains a patch.
How severe is CVE-2026-33396?: CVE-2026-33396 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-33396 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-33396?: CVE-2026-33396 affects Hackerbay Oneuptime. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-33396?: 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.
Does CVE-2026-33396 have an EU (EUVD) identifier?: Yes. CVE-2026-33396 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-16189.
When was CVE-2026-33396 published?: CVE-2026-33396 was published on 2026-03-26 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:hackerbay:oneuptime:*:*:*:*:*:*:*:*

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