Description
fs/nfsd/nfs3xdr.c in the Linux kernel through 5.10.8, when there is an NFS export of a subdirectory of a filesystem, allows remote attackers to traverse to other parts of the filesystem via READDIRPLUS. NOTE: some parties argue that such a subdirectory export is not intended to prevent this attack; see also the exports(5) no_subtree_check default behavior
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 5.10.12-1 | — |
| Debian 13 | linux | 5.10.12-1 | — |
| Debian 12 | linux | 5.10.12-1 | — |
| Debian 9 | linux | 4.9.258-1 | DLA-2586-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux-raspi-realtime | No fix yet | — |
| Ubuntu 22.04 LTS | linux-realtime +1 | No fix yet | — |
| Ubuntu 20.04 LTS | linux | 5.4.0-67.75 | USN-4878-1 |
| Ubuntu 20.04 LTS | linux-aws | 5.4.0-1039.41 | USN-4878-1 |
| Ubuntu 20.04 LTS | linux-azure | 5.4.0-1041.43 | USN-4878-1 |
| Ubuntu 20.04 LTS | linux-gcp | 5.4.0-1038.41 | USN-4878-1 |
| Ubuntu 20.04 LTS | linux-gke | 5.4.0-1037.39 | — |
| Ubuntu 20.04 LTS | linux-gkeop | 5.4.0-1011.12 | USN-4878-1 |
| Ubuntu 20.04 LTS | linux-hwe-5.8 | 5.8.0-49.55~20.04.1 | USN-4910-1 |
| Ubuntu 20.04 LTS | linux-kvm | 5.4.0-1034.35 | USN-4878-1 |
| Ubuntu 20.04 LTS | linux-oem-5.10 | 5.10.0-1014.15 | — |
| Ubuntu 20.04 LTS | linux-oem-5.6 | 5.6.0-1053.57 | USN-4912-1 |
| Ubuntu 20.04 LTS | linux-oracle | 5.4.0-1039.42 | USN-4878-1 |
| Ubuntu 20.04 LTS | linux-raspi | 5.4.0-1030.33 | USN-4878-1 |
| Ubuntu 20.04 LTS | linux-riscv +1 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-riscv-5.8 | 5.8.0-22.24~20.04.1 | — |
| Ubuntu 18.04 LTS | linux | 4.15.0-137.141 | USN-4877-1 |
| Ubuntu 18.04 LTS | linux-aws | 4.15.0-1095.102 | USN-4877-1 |
| Ubuntu 18.04 LTS | linux-aws-5.4 | 5.4.0-1039.41~18.04.1 | USN-4878-1 |
| Ubuntu 18.04 LTS | linux-azure-4.15 | 4.15.0-1109.121 | USN-4877-1 |
| Ubuntu 18.04 LTS | linux-azure-5.4 | 5.4.0-1041.43~18.04.1 | USN-4878-1 |
| Ubuntu 18.04 LTS | linux-dell300x | 4.15.0-1013.17 | USN-4877-1 |
| Ubuntu 18.04 LTS | linux-gcp +13 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp-4.15 | 4.15.0-1094.107 | USN-4877-1 |
| Ubuntu 18.04 LTS | linux-gcp-5.4 | 5.4.0-1038.41~18.04.1 | USN-4878-1 |
| Ubuntu 18.04 LTS | linux-gke-5.4 | 5.4.0-1037.39~18.04.1 | USN-4878-1 |
| Ubuntu 18.04 LTS | linux-gkeop-5.4 | 5.4.0-1011.12~18.04.2 | USN-4878-1 |
| Ubuntu 18.04 LTS | linux-hwe-5.4 | 5.4.0-67.75~18.04.1 | USN-4878-1 |
| Ubuntu 18.04 LTS | linux-kvm | 4.15.0-1086.88 | USN-4877-1 |
| Ubuntu 18.04 LTS | linux-oracle | 4.15.0-1066.74 | USN-4877-1 |
| Ubuntu 18.04 LTS | linux-oracle-5.4 | 5.4.0-1039.42~18.04.1 | USN-4878-1 |
| Ubuntu 18.04 LTS | linux-raspi-5.4 | 5.4.0-1030.33~18.04.1 | USN-4878-1 |
| Ubuntu 18.04 LTS | linux-raspi2 | 4.15.0-1080.85 | USN-4877-1 |
| Ubuntu 18.04 LTS | linux-snapdragon | 4.15.0-1097.106 | USN-4877-1 |
| Ubuntu 16.04 LTS | linux | 4.4.0-204.236 | USN-4876-1 |
| Ubuntu 16.04 LTS | linux-aws | 4.4.0-1123.137 | USN-4876-1 |
| Ubuntu 16.04 LTS | linux-aws-hwe | 4.15.0-1095.102~16.04.1 | USN-4877-1 |
| Ubuntu 16.04 LTS | linux-azure | 4.15.0-1109.121~16.04.1 | USN-4877-1 |
| Ubuntu 16.04 LTS | linux-gcp | 4.15.0-1094.107~16.04.1 | USN-4877-1 |
| Ubuntu 16.04 LTS | linux-hwe | 4.15.0-137.141~16.04.1 | USN-4877-1 |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu 16.04 LTS | linux-kvm | 4.4.0-1089.98 | USN-4876-1 |
| Ubuntu 16.04 LTS | linux-oracle | 4.15.0-1066.74~16.04.1 | USN-4877-1 |
| Ubuntu 16.04 LTS | linux-raspi2 | 4.4.0-1147.157 | USN-4876-1 |
| Ubuntu 16.04 LTS | linux-snapdragon | 4.4.0-1151.161 | USN-4876-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro FIPS 20.04 LTS | linux-aws-fips +2 | No fix yet | — |
| Ubuntu Pro FIPS 18.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS 16.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-aws-fips | 5.4.0-1069.73+fips2 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-azure-fips | 5.4.0-1073.76+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-gcp-fips | 5.4.0-1067.71~20.04.1 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-aws-fips | 4.15.0-2038.40 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-azure-fips | 4.15.0-2021.24 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-fips | 4.15.0-1054.62 | — |
| Ubuntu Pro FIPS-updates 16.04 LTS | linux-fips | 4.4.0-1057.63 | — |
| Ubuntu Pro 20.04 LTS | linux-azure-fde-5.15 | 5.15.0-1114.123~20.04.1 | — |
| Ubuntu Pro 14.04 LTS | linux | No fix yet | — |
| Ubuntu Pro 14.04 LTS | linux-aws | 4.4.0-1087.91 | USN-4876-1 |
| Ubuntu Pro 14.04 LTS | linux-azure | 4.15.0-1109.121~14.04.1 | USN-4877-1 |
| Ubuntu Pro 14.04 LTS | linux-lts-xenial | 4.4.0-204.236~14.04.1 | USN-4876-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | kernel-livepatch-4.14.219-161.340 | 1.0-0.amzn2 | ALAS2-2021-1600 |
| Amazon Linux 2 | perf +8 | 4.14.219-161.340.amzn2 | ALAS2-2021-1600 |
Advisories 7
- USN-4910-1 linux, linux-aws, linux-azure, linux-gcp, linux-hwe-5.8, linux-kvm, linux-oracle, linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- USN-4912-1 linux-oem-5.6 vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- USN-4876-1 linux, linux-aws, linux-kvm, linux-lts-xenial, linux-raspi2, linux-snapdragon vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- USN-4878-1 linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-gcp, linux-gcp-5.4, linux-gke-5.4, linux-gkeop, linux-gkeop-5.4, linux-hwe-5.4, linux-kvm, linux-oracle, linux-oracle-5.4, linux-raspi, linux-raspi-5.4 vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- USN-4877-1 linux, linux-aws, linux-aws-hwe, linux-azure, linux-azure-4.15, linux-dell300x, linux-gcp, linux-gcp-4.15, linux-hwe, linux-kvm, linux-oracle, linux-raspi2, linux-snapdragon vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- DLA-2586-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- ALAS2-2021-1600 Important: kernel security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · May 23, 2024
References
- https://patchwork.kernel.org/project/linux-nfs/patch/20210111210129.GA11652%40fieldses.org/
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=51b2ee7d006a736a9126e8111d1f24e4fd0afaa6
- FEDORA-2021-3bcc7198c8 vendor-advisory
- [debian-lts-announce] 20210309 [SECURITY] [DLA 2586-1] linux security update mailing-list