How severe is CVE-2019-12830?

CVE-2019-12830 has a CVSS 3.x base score of 8.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2019-12830 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-12830?

CVE-2019-12830 affects Mybb. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-12830?

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-2019-12830 published?

CVE-2019-12830 was published on 2019-06-15 and last updated on 2026-06-17.

CVE-2019-12830

CVE-2019-12830 is a high-severity vulnerability in Mybb with a CVSS 3.x base score of 8.7. 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-79.

Key facts

Severity: High (CVSS 3.x base score 8.7)
CVSS v2: 3.5
EPSS exploit prediction: 1% (58th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Mybb
Published: 2019-06-15
Last modified: 2026-06-17

Description

In MyBB before 1.8.21, an attacker can exploit a parsing flaw in the Private Message / Post renderer that leads to [video] BBCode persistent XSS to take over any forum account, aka a nested video MyCode issue.

Frequently asked questions

What is CVE-2019-12830?: In MyBB before 1.8.21, an attacker can exploit a parsing flaw in the Private Message / Post renderer that leads to [video] BBCode persistent XSS to take over any forum account, aka a nested video MyCode issue.
How severe is CVE-2019-12830?: CVE-2019-12830 has a CVSS 3.x base score of 8.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2019-12830 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-12830?: CVE-2019-12830 affects Mybb. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-12830?: 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-2019-12830 published?: CVE-2019-12830 was published on 2019-06-15 and last updated on 2026-06-17.

References

Affected products (1)

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

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