CVE-2021-47259
In the Linux kernel, the following vulnerability has been resolved: NFS: Fix use-after-free in nfs4_init_client() KASAN reports a use-after-free when attempting to mount two different exports through two different NICs that belong to the same server.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.71%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: NFS: Fix use-after-free in nfs4_init_client() KASAN reports a use-after-free when attempting to mount two different exports through two different NICs that belong to the same server. Olga was able to hit this with kernels starting somewhere between 5.7 and 5.10, but I traced the patch that introduced the clear_bit() call to 4.13. So something must have changed in the refcounting of the clp pointer to make this call to nfs_put_client() the very last one.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.71% probability · 51th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/3e3c7ebbfac152d08be75c92802a64a1f6471a15Patch
- https://git.kernel.org/stable/c/42c10b0db064e45f5c5ae7019bbf2168ffab766cPatch
- https://git.kernel.org/stable/c/476bdb04c501fc64bf3b8464ffddefc8dbe01577Patch
- https://git.kernel.org/stable/c/72651c6579a25317a90536181d311c663d0329abPatch
- https://git.kernel.org/stable/c/c3b6cf64dfe4ef96e7341508d50d6998da7062c7Patch
- https://git.kernel.org/stable/c/c7eab9e2d7b4e983ce280276fb920af649955897Patch
- https://git.kernel.org/stable/c/3e3c7ebbfac152d08be75c92802a64a1f6471a15Patch
- https://git.kernel.org/stable/c/42c10b0db064e45f5c5ae7019bbf2168ffab766cPatch
- https://git.kernel.org/stable/c/476bdb04c501fc64bf3b8464ffddefc8dbe01577Patch
- https://git.kernel.org/stable/c/72651c6579a25317a90536181d311c663d0329abPatch
- https://git.kernel.org/stable/c/c3b6cf64dfe4ef96e7341508d50d6998da7062c7Patch
- https://git.kernel.org/stable/c/c7eab9e2d7b4e983ce280276fb920af649955897Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.