Which versions of glibc do different versions of RedHat ship with?
DistroWatch typically has a pretty good run down of what each distro has.
Red Hat's run down
Edit: The RedHat documentation used to list the version of the libraries they included. They have since removed that information.
This data is from distrowatch. Sorry for the sideways scroll and long ASCII text. StackOverflow doesn't support Markdown Tables.
| Package | RHEL-8.0 | RHEL-7.5 | RHEL-6.9 | RHEL-5.11 | RHEL-4.8 | RHEL-3.9 | RHEL-2.1 | 9 | 8.0 | 7.3 | 7.2 | 7.1 | 7.0 | 6.2 | 6.1 | 6.0 | 5.2 | 5.1 | 5.0 | 4.2 |
| | | | | | | | | shrike | psyche | valhalla | enigma | seawolf | guiness | zoot | cartman | hedwig | apollo | manhattan | hurricane | biltmore |
| glibc (2.29) | 2.28 | 2.17 | 2.12 | 2.5 | 2.3.4 | 2.3.2 | 2.2.4 | 2.3.2 | 2.2.93 | 2.2.5 | 2.2.4 | 2.2.2 | 2.1.92 | 2.1.3 | 2.1.2 | 2.1.1 | 2.0.7 | 2.0.7 | 2.0.5c | -- |
It used to be available from RedHat documentation: RHEL 6 RHEL 7