How severe is CVE-2023-53977?

CVE-2023-53977 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-2023-53977 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-53977?

CVE-2023-53977 affects Mybb. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-53977?

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

Does CVE-2023-53977 have an EU (EUVD) identifier?

Yes. CVE-2023-53977 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-60239.

When was CVE-2023-53977 published?

CVE-2023-53977 was published on 2025-12-22 and last updated on 2026-06-17.

CVE-2023-53977

CVE-2023-53977 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 v4: 5.1
EPSS exploit prediction: 0% (9th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2023-60239
Weakness: CWE-79
Affected product: Mybb
Published: 2025-12-22
Last modified: 2026-06-17

Description

myBB Forums 1.8.26 contains a stored cross-site scripting vulnerability in the forum management system that allows authenticated administrators to inject malicious scripts when creating new forums. Attackers can exploit this vulnerability by inserting script payloads in the forum title field when adding new forums through the 'Forums and Posts' > 'Forum Management' interface, causing arbitrary JavaScript to execute when the forum listing is viewed.

Frequently asked questions

What is CVE-2023-53977?: myBB Forums 1.8.26 contains a stored cross-site scripting vulnerability in the forum management system that allows authenticated administrators to inject malicious scripts when creating new forums. Attackers can exploit this vulnerability by inserting script payloads in the forum title field when adding new forums through the 'Forums and Posts' > 'Forum Management' interface, causing arbitrary JavaScript to execute when the forum listing is viewed.
How severe is CVE-2023-53977?: CVE-2023-53977 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-2023-53977 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-53977?: CVE-2023-53977 affects Mybb. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-53977?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2023-53977 have an EU (EUVD) identifier?: Yes. CVE-2023-53977 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-60239.
When was CVE-2023-53977 published?: CVE-2023-53977 was published on 2025-12-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mybb:mybb:1.8.26:*:*:*:*:*:*:*

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