How severe is CVE-2021-27946?

CVE-2021-27946 has a CVSS 3.x base score of 8.8, rated high 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-2021-27946 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27946?

CVE-2021-27946 affects Mybb. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27946?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-27946 published?

CVE-2021-27946 was published on 2021-03-15 and last updated on 2026-06-17.

CVE-2021-27946

CVE-2021-27946 is a high-severity vulnerability in Mybb with a CVSS 3.x base score of 8.8. 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-89.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.5
EPSS exploit prediction: 4% (90th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-89
Affected product: Mybb
Published: 2021-03-15
Last modified: 2026-06-17

Description

SQL Injection vulnerability in MyBB before 1.8.26 via poll vote count. (issue 1 of 3).

Frequently asked questions

What is CVE-2021-27946?: SQL Injection vulnerability in MyBB before 1.8.26 via poll vote count. (issue 1 of 3).
How severe is CVE-2021-27946?: CVE-2021-27946 has a CVSS 3.x base score of 8.8, rated high 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-2021-27946 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27946?: CVE-2021-27946 affects Mybb. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27946?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-27946 published?: CVE-2021-27946 was published on 2021-03-15 and last updated on 2026-06-17.

References

Affected products (1)

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

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CVE-2011-5133 — Critical (CVSS 10.0): Unspecified vulnerability in MyBB before 1.6.5 has unknown impact and attack vectors, related to an "unparsed user…
CVE-2006-0218 — Critical (CVSS 10.0): Multiple unspecified vulnerabilities in MyBulletinBoard (MyBB) before 1.0.2 have unspecified impact and attack vectors,…
CVE-2011-10018 — Critical (CVSS 9.8): myBB version 1.6.4 was distributed with an unauthorized backdoor embedded in the source code. The backdoor allowed…
CVE-2020-22612 — Critical (CVSS 9.8): Installer RCE on settings file write in MyBB before 1.8.22.

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