Description
In the Linux kernel, the following vulnerability has been resolved:
net: fix a memleak when uncloning an skb dst and its metadata
When uncloning an skb dst and its associated metadata, a new
dst+metadata is allocated and later replaces the old one in the skb.
This is helpful to have a non-shared dst+metadata attached to a specific
skb.
The issue is the uncloned dst+metadata is initialized with a refcount of
1, which is increased to 2 before attaching it to the skb. When
tun_dst_unclone returns, the dst+metadata is only referenced from a
single place (the skb) while its refcount is 2. Its refcount will never
drop to 0 (when the skb is consumed), leading to a memory leak.
Fix this by removing the call to dst_hold in tun_dst_unclone, as the
dst+metadata refcount is already 1.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 4.3 | 4.9.302 |
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 | 5.16.10-1 | — |
| Debian 13 | linux | 5.16.10-1 | — |
| Debian 12 | linux | 5.16.10-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux-raspi-realtime | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv +25 | No fix yet | — |
| Ubuntu 20.04 LTS | linux | 5.4.0-110.124 | — |
| Ubuntu 20.04 LTS | linux-aws +1 | 5.4.0-1073.78 | — |
| Ubuntu 20.04 LTS | linux-azure | 5.4.0-1078.81 | — |
| Ubuntu 20.04 LTS | linux-bluefield | 5.4.0-1040.44 | — |
| Ubuntu 20.04 LTS | linux-gke +26 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gkeop | 5.4.0-1040.41 | — |
| Ubuntu 20.04 LTS | linux-ibm | 5.4.0-1021.23 | — |
| Ubuntu 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1008.11~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-iot | 5.4.0-1004.6 | — |
| Ubuntu 20.04 LTS | linux-kvm | 5.4.0-1063.66 | — |
| Ubuntu 20.04 LTS | linux-oracle | 5.4.0-1071.77 | — |
| Ubuntu 20.04 LTS | linux-raspi | 5.4.0-1060.68 | — |
| Ubuntu 18.04 LTS | linux | 4.15.0-177.186 | — |
| Ubuntu 18.04 LTS | linux-aws | 4.15.0-1128.137 | — |
| Ubuntu 18.04 LTS | linux-aws-5.4 | 5.4.0-1075.80~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-azure-4.15 | 4.15.0-1138.151 | — |
| Ubuntu 18.04 LTS | linux-azure-5.4 | 5.4.0-1078.81~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp-4.15 | 4.15.0-1122.136 | — |
| Ubuntu 18.04 LTS | linux-gcp-5.4 | 5.4.0-1073.78~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-hwe-5.4 | 5.4.0-110.124~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-ibm-5.4 | 5.4.0-1021.23~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-kvm | 4.15.0-1114.117 | — |
| Ubuntu 18.04 LTS | linux-oracle | 4.15.0-1093.102 | — |
| Ubuntu 18.04 LTS | linux-oracle-5.4 | 5.4.0-1071.77~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-raspi-5.4 | 5.4.0-1060.68~18.04.1 | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro FIPS 20.04 LTS | linux-fips +3 | 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 +1 | 5.4.0-1073.78+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-azure-fips | 5.4.0-1078.81+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips | 5.4.0-1049.55 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-aws-fips | 4.15.0-2067.70 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-azure-fips | 4.15.0-2049.53 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-fips | 4.15.0-1085.94 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-gcp-fips | 4.15.0-2032.35 | — |
| Ubuntu Pro FIPS-updates 16.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro 16.04 LTS | linux +2 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | linux-aws-hwe | 4.15.0-1128.137~16.04.1 | — |
| Ubuntu Pro 16.04 LTS | linux-azure | 4.15.0-1138.151~16.04.1 | — |
| Ubuntu Pro 16.04 LTS | linux-gcp | 4.15.0-1122.136~16.04.1 | — |
| Ubuntu Pro 16.04 LTS | linux-hwe | 4.15.0-177.186~16.04.1 | — |
| Ubuntu Pro 16.04 LTS | linux-oracle | 4.15.0-1093.102~16.04.1 | — |
| Ubuntu Pro 14.04 LTS | linux-aws +1 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | linux-azure | 4.15.0-1138.151~14.04.1 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP5 | kernel-64kb +5 | 5.14.21-150500.55.73.1 | SUSE-SU-2024:2939-1 |
| SLES 15 SP5 | kernel-azure +2 | 5.14.21-150500.33.63.1 | SUSE-SU-2024:2947-1 |
| SLES 15 SP5 | kernel-default-base | 5.14.21-150500.55.73.1.150500.6.33.8 | SUSE-SU-2024:2939-1 |
| SLES 15 SP5 | kernel-docs | 5.14.21-150500.55.73.2 | SUSE-SU-2024:2939-1 |
| SLES 12 SP5 | kernel-syms +2 | 4.12.14-122.234.1 | SUSE-SU-2025:0034-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLE Micro 5.5 | kernel-default | 5.14.21-150500.55.73.1 | SUSE-SU-2024:2939-1 |
| SLE Micro 5.5 | kernel-default-base | 5.14.21-150500.55.73.1.150500.6.33.8 | SUSE-SU-2024:2939-1 |
| SLE Micro 5.5 | kernel-rt +1 | 5.14.21-150500.13.64.1 | SUSE-SU-2024:2894-1 |
| SLE Live Patching 15 SP5 | kernel-default | 5.14.21-150500.55.73.1 | SUSE-SU-2024:2939-1 |
| SLE Live Patching 15 SP5 | kernel-livepatch-SLE15-SP5_Update_17 +1 | 1-150500.11.3.1 | SUSE-SU-2024:2939-1, SUSE-SU-2024:2894-1 |
| SLE Live Patching 12 SP5 | kernel-default | 4.12.14-122.234.1 | SUSE-SU-2024:4100-1 |
| SLE Live Patching 12 SP5 | kgraft-patch-SLE12-SP5_Update_62 | 1-8.3.1 | SUSE-SU-2024:4100-1 |
| SUSE Real Time Module 15 SP5 | kernel-rt +3 | 5.14.21-150500.13.64.1 | SUSE-SU-2024:2894-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.5 | dtb-aarch64 +9 | 5.14.21-150500.55.73.1 | SUSE-SU-2024:2939-1 |
| openSUSE Leap 15.5 | kernel-azure +2 | 5.14.21-150500.33.63.1 | SUSE-SU-2024:2947-1 |
| openSUSE Leap 15.5 | kernel-default-base | 5.14.21-150500.55.73.1.150500.6.33.8 | SUSE-SU-2024:2939-1 |
| openSUSE Leap 15.5 | kernel-docs | 5.14.21-150500.55.73.2 | SUSE-SU-2024:2939-1 |
| openSUSE Leap 15.5 | kernel-rt +3 | 5.14.21-150500.13.64.1 | SUSE-SU-2024:2894-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap Micro 5.5 | kernel-default | 5.14.21-150500.55.73.1 | SUSE-SU-2024:2939-1 |
| openSUSE Leap Micro 5.5 | kernel-default-base | 5.14.21-150500.55.73.1.150500.6.33.8 | SUSE-SU-2024:2939-1 |
| openSUSE Leap Micro 5.5 | kernel-rt | 5.14.21-150500.13.64.1 | SUSE-SU-2024:2894-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | kernel-livepatch-4.14.268-205.500 | 1.0-0.amzn2 | ALAS2-2022-1761 |
| Amazon Linux 2 | perf +8 | 4.14.268-205.500.amzn2 | ALAS2-2022-1761 |
Advisories 7
- WID-SEC-2024-1625 Linux Kernel: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff BSI CERT-Bund (WID) · Jul 27, 2026
- SUSE-SU-2025:0034-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:2947-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:2939-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:4100-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- ALAS2-2022-1761 Important: kernel security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Oct 2, 2025
- SUSE-SU-2024:2894-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · May 2, 2025
References
- https://git.kernel.org/stable/c/4ac84498fbe84a00e7aef185e2bb3e40ce71eca4
- https://git.kernel.org/stable/c/c1ff27d100e2670b03cbfddb9117e5f9fc672540
- https://git.kernel.org/stable/c/0be943916d781df2b652793bb2d3ae4f9624c10a
- https://git.kernel.org/stable/c/a80817adc2a4c1ba26a7aa5f3ed886e4a18dff88
- https://git.kernel.org/stable/c/00e6d6c3bc14dfe32824e2c515f0e0f2d6ecf2f1
- https://git.kernel.org/stable/c/fdcb263fa5cda15b8cb24a641fa2718c47605314
- https://git.kernel.org/stable/c/8b1087b998e273f07be13dcb5f3ca4c309c7f108
- https://git.kernel.org/stable/c/9eeabdf17fa0ab75381045c867c370f4cc75a613