CVE-2026-6104
In PHP versions 8.4.* before 8.4.21 and 8.5.* before 8.5.6, when an encoding name containing an embedded NUL byte is passed to mb_convert_encoding() or related mbstring functions, the code incorrectly assumes that when strncasecmp() returns 0 it means the strings have the same length. This can lead to out-of-bounds read of global memory, potentially causing a crash or information disclosure or crash. Affected functions include mb_convert_encoding(), mb_detect_encoding(), mb_convert_variables(), and mb_detect_order(), as well as the mbstring.detect_order and mbstring.http_output INI settings.
Exploitation Probability (EPSS)
Low PriorityThe Exploit Prediction Scoring System (EPSS) uses machine learning to estimate the probability that a vulnerability will be exploited in the wild within the next 30 days.
7-Day Exploitation Trend
Vulnerability Timeline
2 eventsThreat Actor Attribution
PREMIUM INTELRemediation & Mitigation
SOLUTIONOfficial patches and mitigation steps are available for this vulnerability.
apt-get update && apt-get upgrade -y specific-package
# Verify installation
dpkg -l | grep package-name
Affected Products
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Check your domain or package.json for CVE-2026-6104 exposure.
Vulnerability Details
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