It is almost certainly the latter, since it is another “Customer Security Advisory”. There is a currently open report for a tranche of nginx vulnerabilities[0] and a closed report for PwnEscape[1] and the PHP RCE[2] that are identical. The HN topic has been editorialised.

[0] https://status.linode.com/incidents/8dqqkh4d9y2c

[1] https://status.linode.com/incidents/zp71823t318w

[2] https://status.linode.com/incidents/wq8zlhk736fk