How severe is CVE-2020-19049?

CVE-2020-19049 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2020-19049 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-19049?

CVE-2020-19049 affects Mybb. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-19049?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-19049 published?

CVE-2020-19049 was published on 2021-08-31 and last updated on 2026-06-17.

CVE-2020-19049

CVE-2020-19049 is a medium-severity vulnerability in Mybb with a CVSS 3.x base score of 5.4. 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: Medium (CVSS 3.x base score 5.4)
CVSS v2: 3.5
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Mybb
Published: 2021-08-31
Last modified: 2026-06-17

Description

Cross Site Scripting (XSS) in MyBB v1.8.20 allows remote attackers to inject arbitrary web script or HTML via the "Description" field found in the "Add New Forum" page by doing an authenticated POST HTTP request to '/Upload/admin/index.php?module=forum-management&action=add'.

Frequently asked questions

What is CVE-2020-19049?: Cross Site Scripting (XSS) in MyBB v1.8.20 allows remote attackers to inject arbitrary web script or HTML via the "Description" field found in the "Add New Forum" page by doing an authenticated POST HTTP request to '/Upload/admin/index.php?module=forum-management&action=add'.
How severe is CVE-2020-19049?: CVE-2020-19049 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2020-19049 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-19049?: CVE-2020-19049 affects Mybb. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-19049?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-19049 published?: CVE-2020-19049 was published on 2021-08-31 and last updated on 2026-06-17.

References

https://github.com/joelister/bug/issues/2

Affected products (1)

cpe:2.3:a:mybb:mybb:1.8.20:*:*:*:*:*:*:*

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