CVE-2024-36892mm/slub: avoid zeroing outside-object freepointer for single free

Description

In the Linux kernel, the following vulnerability has been resolved: mm/slub: avoid zeroing outside-object freepointer for single free Commit 284f17ac13fe ("mm/slub: handle bulk and single object freeing separately") splits single and bulk object freeing in two functions slab_free() and slab_free_bulk() which leads slab_free() to call slab_free_hook() directly instead of slab_free_freelist_hook(). If `init_on_free` is set, slab_free_hook() zeroes the object. Afterward, if `slub_debug=F` and `CONFIG_SLAB_FREELIST_HARDENED` are set, the do_slab_free() slowpath executes freelist consistency checks and try to decode a zeroed freepointer which leads to a "Freepointer corrupt" detection in check_object(). During bulk free, slab_free_freelist_hook() isn't affected as it always sets it objects freepointer using set_freepointer() to maintain its reconstructed freelist after `init_on_free`. For single free, object's freepointer thus needs to be avoided when stored outside the object if `init_on_free` is set. The freepointer left as is, check_object() may later detect an invalid pointer value due to objects overflow. To reproduce, set `slub_debug=FU init_on_free=1 log_level=7` on the command line of a kernel build with `CONFIG_SLAB_FREELIST_HARDENED=y`. dmesg sample log: [ 10.708715] ============================================================================= [ 10.710323] BUG kmalloc-rnd-05-32 (Tainted: G B T ): Freepointer corrupt [ 10.712695] ----------------------------------------------------------------------------- [ 10.712695] [ 10.712695] Slab 0xffffd8bdc400d580 objects=32 used=4 fp=0xffff9d9a80356f80 flags=0x200000000000a00(workingset|slab|node=0|zone=2) [ 10.716698] Object 0xffff9d9a80356600 @offset=1536 fp=0x7ee4f480ce0ecd7c [ 10.716698] [ 10.716698] Bytes b4 ffff9d9a803565f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [ 10.720703] Object ffff9d9a80356600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [ 10.720703] Object ffff9d9a80356610: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [ 10.724696] Padding ffff9d9a8035666c: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [ 10.724696] Padding ffff9d9a8035667c: 00 00 00 00 .... [ 10.724696] FIX kmalloc-rnd-05-32: Object at 0xffff9d9a80356600 not freed

Timeline

Scores

EPSS (exploitation in 30 days)

0.20% · top 91% of all CVEs (14 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.

Affected products

• Linux · Linux

  • affected 284f17ac13fe34ae9eecbe57bb91553374d9b855 – < 56900355485f6e82114b18c812edd57fd7970dcb
  • affected 284f17ac13fe34ae9eecbe57bb91553374d9b855 – < 8f828aa48812ced28aa39cb3cfe55ef2444d03dd

• Linux · Linux

  • affected 6.8
  • unaffected < 6.8
  • unaffected 6.8.10 – ≤ 6.8.*
  • unaffected 6.9 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2024-36244 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2024-36892](https://cveledger.app/badge/CVE-2024-36892.svg)](https://cveledger.app/cve/CVE-2024-36892)

Record last updated 11 May 2026, 20:16 UTC.