4chan restricts posting during emergency PHP security update

4chan restricted its forum to read-only operation on October 21, 2026, while awaiting an urgent PHP security update, according to reporting quoting the service's notice. The restriction prevented normal posting while reading remained available. Polygon also listed 4chan among services taken offline or placed in read-only mode during the vulnerability response. The platform describes itself as a U.S. forum service. The reports do not establish that attackers compromised 4chan, and exploitation attempts against PHP elsewhere do not prove exploitation of this site. Its homepage was accessible when checked, but complete restoration of posting was not independently confirmed.