hb-ot-layout-gsubgpos.hh in HarfBuzz through 6.0.0 allows attackers to trigger O(n^2) growth via consecutive marks during the process of looking back for base glyphs when attaching marks.
chromium.googlesource.com/chromium/src/+/e1f324aa681af54101c1f2d173d92adb80e37088/DEPS#361
github.com/harfbuzz/harfbuzz/blob/2822b589bc837fae6f66233e2cf2eef0f6ce8470/src/hb-ot-layout-gsubgpos.hh
github.com/harfbuzz/harfbuzz/commit/85be877925ddbf34f74a1229f3ca1716bb6170dc
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KWCHWSICWVZSAXP2YAXM65JC2GR53547/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YZ5M2GSAIHFPLHYJXUPQ2QDJCLWXUGO3/
security.netapp.com/advisory/ntap-20230725-0006/