Details for this vulnerability have not been published by NIST at this point. Descriptions from software vendor advisories for this issue are provided below.
Chrome Releases reports:
This update include 6 security fixes:
1169317] Critical CVE-2021-21142: Use after free in Payments.
Reported by Khalil Zhani on 2021-01-21
 High CVE-2021-21143: Heap buffer overflow in
Extensions. Reported by Allen Parker and Alex Morgan of MU on
 High CVE-2021-21144: Heap buffer overflow in Tab
Groups. Reported by Leecraso and Guang Gong of 360 Alpha Lab on
 High CVE-2021-21145: Use after free in Fonts. Reported
by Anonymous on 2020-12-03
 High CVE-2021-21146: Use after free in Navigation.
Reported by Alison Huffman and Choongwoo Han of Microsoft Browser
Vulnerability Research on 2020-12-24
 Medium CVE-2021-21147: Inappropriate implementation in
Skia. Reported by Roman Starkov on 2021-01-04