# CVE-2021-47218: linux: In the Linux kernel, the following vulnerability has been resolved:  selinux: fix NULL-pointer dereference when hasht...

CVE-2021-47218 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47218, released April 10, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-47218
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0023
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Apr 10, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  selinux: fix NULL-pointer dereference when hashtab allocation fails  When the hash table slot array allocation fails in hashtab_init(), h->size is left initialized with a non-zero value, but the h->htable pointer is NULL. This may then cause a NULL pointer dereference, since the policydb code relies on the assumption that even after a failed hashtab_init(), hashtab_map() and hashtab_destroy() can be safely called on it. Yet, these detect an empty hashtab only by looking at the size.  Fix this by making sure that hashtab_init() always leaves behind a valid empty hashtab when the allocation fails.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.15.5-1 | [DEBIAN-CVE-2021-47218](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47218.md) | Apr 10, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.15.5-1 | [DEBIAN-CVE-2021-47218](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47218.md) | Apr 10, 2024 |
| Linux | linux Debian 14 | 5.15.5-1 | [DEBIAN-CVE-2021-47218](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47218.md) | Apr 10, 2024 |

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