How severe is CVE-2026-33640?

CVE-2026-33640 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-2026-33640 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-33640?

CVE-2026-33640 affects Getoutline Outline. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-33640?

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-2026-33640 have an EU (EUVD) identifier?

Yes. CVE-2026-33640 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-16415.

When was CVE-2026-33640 published?

CVE-2026-33640 was published on 2026-03-26 and last updated on 2026-06-17.

CVE-2026-33640

CVE-2026-33640 is a critical-severity vulnerability in Getoutline Outline 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-307.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 9.1
EPSS exploit prediction: 0% (37th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-16415
Weakness: CWE-307
Affected product: Getoutline Outline
Published: 2026-03-26
Last modified: 2026-06-17

Description

Outline is a service that allows for collaborative documentation. Outline implements an Email OTP login flow for users not associated with an Identity Provider. Starting in version 0.86.0 and prior to version 1.6.0, Outline does not invalidate OTP codes based on amount or frequency of invalid submissions, rather it relies on the rate limiter to restrict attempts. Consequently, identified bypasses in the rate limiter permit unrestricted OTP code submissions within the codes lifetime. This allows attackers to perform brute force attacks which enable account takeover. Version 1.6.0 fixes the issue.

Frequently asked questions

What is CVE-2026-33640?: Outline is a service that allows for collaborative documentation. Outline implements an Email OTP login flow for users not associated with an Identity Provider. Starting in version 0.86.0 and prior to version 1.6.0, Outline does not invalidate OTP codes based on amount or frequency of invalid submissions, rather it relies on the rate limiter to restrict attempts. Consequently, identified bypasses in the rate limiter permit unrestricted OTP code submissions within the codes lifetime. This allows attackers to perform brute force attacks which enable account takeover. Version 1.6.0 fixes the issue.
How severe is CVE-2026-33640?: CVE-2026-33640 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-2026-33640 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-33640?: CVE-2026-33640 affects Getoutline Outline. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-33640?: 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-2026-33640 have an EU (EUVD) identifier?: Yes. CVE-2026-33640 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-16415.
When was CVE-2026-33640 published?: CVE-2026-33640 was published on 2026-03-26 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:getoutline:outline:*:*:*:*:*:*:*:*

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