Description
U-Boot before 2026.10-rc5 contains a buffer overflow in nfs_readlink_reply() function in net/nfs-common.c when processing NFS server responses. A malicious NFS server can send crafted READLINK replies with negative or oversized symlink length values to corrupt memory and crash the bootloader.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| u-boot | u-boot | < 2026.10-rc5 | 2026.10-rc5 |
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 | u-boot | No fix yet | — |
| Debian 13 | u-boot | No fix yet | — |
| Debian 12 | u-boot | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | u-boot | 2025.10-0ubuntu6 | USN-8930-2 |
| Ubuntu 26.04 LTS | u-boot | 2025.10-0ubuntu2.2 | USN-8930-1 |
| Ubuntu 24.04 LTS | u-boot | 2025.10-0ubuntu0.24.04.4 | USN-8930-1 |
| Ubuntu 24.04 LTS | u-boot-nezha | No fix yet | — |
| Ubuntu 22.04 LTS | u-boot | 2022.01+dfsg-2ubuntu2.9 | USN-8930-1 |
| Ubuntu 22.04 LTS | u-boot-nezha | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | u-boot | 2021.01+dfsg-3ubuntu0~20.04.6+esm2 | USN-8930-1 |
| Ubuntu Pro 18.04 LTS | u-boot | 2020.10+dfsg-1ubuntu0~18.04.3+esm2 | USN-8930-1 |
| Ubuntu Pro 16.04 LTS | u-boot | 2016.01+dfsg1-2ubuntu5+esm2 | USN-8930-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | qemu | No fix yet | — |
Advisories 3
- USN-8930-2 u-boot vulnerabilities Ubuntu Security Notices (USN) · Oct 21, 2026
- WID-SEC-2026-3660 DENX U-Boot: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 21, 2026
- USN-8930-1 u-boot vulnerabilities Ubuntu Security Notices (USN) · Oct 17, 2026
References
- https://github.com/u-boot/u-boot/commit/1c0aff3a5fbfeee7a8948f624e0b8554e6e0d8fd patch
- https://github.com/u-boot/u-boot/blob/v2026.07/net/nfs-common.c#L643 technical-description
- https://github.com/u-boot/u-boot product
- VulnCheck Advisory: U-Boot before 2026.10-rc5 Buffer Overflow via NFS READLINK third-party-advisory