CVE & CISA-KEV Catalog

CVE-2019-12831

HIGHEPSS 71th pctl
7.2
CVSS v3
NVD

Description

In MyBB before 1.8.21, an attacker can abuse a default behavior of MySQL on many systems (that leads to truncation of strings that are too long for a database column) to create a PHP shell in the cache directory of a targeted forum via a crafted XML import, as demonstrated by truncation of aaaaaaaaaaaaaaaaaaaaaaaaaa.php.css to aaaaaaaaaaaaaaaaaaaaaaaaaa.php with a 30-character limit, aka theme import stylesheet name RCE.

CWE-20Improper Input Validation

How to fix

Remediation Available
mybbNVD
Affected:< 1.8.21Fixed in:1.8.21CVE-2019-12831derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredHigh
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

1.49%probability of exploitation in 30 days
71stpercentile

Elevated risk: more likely to be exploited than 71% of all known CVEs.

References

Vendor Advisory1

Related Vulnerabilities

Other CWE-20 (Improper Input Validation) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2024-3400Critical10.0100%KEV + Ransom-
CVE-2021-45105Medium5.9100%-Fix
CVE-2021-44228Critical10.0100%KEV + RansomFix
CVE-2021-21985Critical9.8100%KEV + RansomFix
CVE-2018-7600Critical9.8100%KEV + RansomFix
CVE-2020-3452High7.5100%KEVFix
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Markdown

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HTML

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.