How severe is CVE-2011-10018?

CVE-2011-10018 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-2011-10018 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-10018?

CVE-2011-10018 affects Mybb. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2011-10018?

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-2011-10018 have an EU (EUVD) identifier?

Yes. CVE-2011-10018 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2011-5246.

When was CVE-2011-10018 published?

CVE-2011-10018 was published on 2025-08-13 and last updated on 2026-06-16.

CVE-2011-10018

CVE-2011-10018 is a critical-severity vulnerability in Mybb 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-94.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 10.0
EPSS exploit prediction: 2% (77th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2011-5246
Weakness: CWE-94
Affected product: Mybb
Published: 2025-08-13
Last modified: 2026-06-16

Description

myBB version 1.6.4 was distributed with an unauthorized backdoor embedded in the source code. The backdoor allowed remote attackers to execute arbitrary PHP code by injecting payloads into a specially crafted collapsed cookie. This vulnerability was introduced during packaging and was not part of the intended application logic. Exploitation requires no authentication and results in full compromise of the web server under the context of the web application.

Frequently asked questions

What is CVE-2011-10018?: myBB version 1.6.4 was distributed with an unauthorized backdoor embedded in the source code. The backdoor allowed remote attackers to execute arbitrary PHP code by injecting payloads into a specially crafted collapsed cookie. This vulnerability was introduced during packaging and was not part of the intended application logic. Exploitation requires no authentication and results in full compromise of the web server under the context of the web application.
How severe is CVE-2011-10018?: CVE-2011-10018 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-2011-10018 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-10018?: CVE-2011-10018 affects Mybb. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2011-10018?: 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-2011-10018 have an EU (EUVD) identifier?: Yes. CVE-2011-10018 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2011-5246.
When was CVE-2011-10018 published?: CVE-2011-10018 was published on 2025-08-13 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:a:mybb:mybb:1.6.4:*:*:*:*:*:*:*

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