How severe is CVE-2025-48940?

CVE-2025-48940 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-48940 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-48940?

CVE-2025-48940 affects Mybb. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-48940?

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.

Does CVE-2025-48940 have an EU (EUVD) identifier?

Yes. CVE-2025-48940 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-16668.

When was CVE-2025-48940 published?

CVE-2025-48940 was published on 2025-06-02 and last updated on 2026-06-17.

CVE-2025-48940

CVE-2025-48940 is a high-severity vulnerability in Mybb with a CVSS 3.x base score of 7.2. 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-22.

Key facts

Severity: High (CVSS 3.x base score 7.2)
EPSS exploit prediction: 0% (37th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-16668
Weakness: CWE-22
Affected product: Mybb
Published: 2025-06-02
Last modified: 2026-06-17

Description

MyBB is free and open source forum software. Prior to version 1.8.39, the upgrade component does not validate user input properly, which allows attackers to perform local file inclusion (LFI) via a specially crafted parameter value. In order to exploit the vulnerability, the installer must be unlocked (no `install/lock` file present) and the upgrade script must be accessible (by re-installing the forum via access to `install/index.php`; when the forum has not yet been installed; or the attacker is authenticated as a forum administrator). MyBB 1.8.39 resolves this issue.

Frequently asked questions

What is CVE-2025-48940?: MyBB is free and open source forum software. Prior to version 1.8.39, the upgrade component does not validate user input properly, which allows attackers to perform local file inclusion (LFI) via a specially crafted parameter value. In order to exploit the vulnerability, the installer must be unlocked (no `install/lock` file present) and the upgrade script must be accessible (by re-installing the forum via access to `install/index.php`; when the forum has not yet been installed; or the attacker is authenticated as a forum administrator). MyBB 1.8.39 resolves this issue.
How severe is CVE-2025-48940?: CVE-2025-48940 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-48940 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-48940?: CVE-2025-48940 affects Mybb. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-48940?: 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.
Does CVE-2025-48940 have an EU (EUVD) identifier?: Yes. CVE-2025-48940 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-16668.
When was CVE-2025-48940 published?: CVE-2025-48940 was published on 2025-06-02 and last updated on 2026-06-17.

References

Affected products (1)

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

More vulnerabilities in Mybb

CVE-2015-8974 — Critical (CVSS 10.0): SQL injection vulnerability in the Group Promotions module in the admin control panel in MyBB (aka MyBulletinBoard)…
CVE-2015-2786 — Critical (CVSS 10.0): Unspecified vulnerability in MyBB (aka MyBulletinBoard) before 1.8.4 has unknown attack vectors related to "Group join…
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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