In the Linux kernel, the following vulnerability has been resolved:
net: Only allow init netns to set default tcp cong to a restricted algo
tcp_set_default_congestion_control() is netns-safe in that it writes to &net->ipv4.tcp_congestion_control, but it also sets ca->flags |= TCP_CONG_NON_RESTRICTED which is not namespaced. This has the unintended side-effect of changing the global net.ipv4.tcp_allowed_congestion_control sysctl, despite the fact that it is read-only: 97684f0970f6 ("net: Make tcp_allowed_congestion_control readonly in non-init netns")
Resolve this netns "leak" by only allowing the init netns to set the default algorithm to one that is restricted. This restriction could be removed if tcp_allowed_congestion_control were namespace-ified in the future.
This bug was uncovered with https://github.com/JonathonReinhart/linux-netns-sysctl-verify
CVSS Details
- CVSS 3.1 Base Score: 7.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade python-perfUpgrade kernel-toolsUpgrade perf-debuginfoUpgrade bpftool-debuginfoUpgrade perfUpgrade kernel-debuginfo-common-aarch64Upgrade bpftoolUpgrade kernel-tools-develUpgrade kernelUpgrade python-perf-debuginfoUpgrade kernel-tools-debuginfoUpgrade kernel-headersUpgrade kernel-debuginfoUpgrade kernel-develUpgrade kernel-debuginfo-common-x86_64 | Jun 11, 2024 | Feb 28, 2024 |
| Debian | — | Upgrade linux | Jul 30, 2024 | Feb 28, 2024 |
| Huawei Euleros 2_0_sp8 | — | Upgrade bpftoolUpgrade kernel-toolsUpgrade python-perfUpgrade kernel-tools-libsUpgrade perfUpgrade kernelUpgrade kernel-headersUpgrade python3-perfUpgrade kernel-devel | Jul 23, 2024 | Feb 28, 2024 |
| Redhat_linux | — | No solution exists | Jul 9, 2025 | Feb 28, 2024 |
| Ubuntu | — | Upgrade linux-bluefieldUpgrade linux-oracle-5.4Upgrade linux-raspi-5.4Upgrade linux-awsUpgrade linux-raspiUpgrade linux-aws-5.4Upgrade linuxUpgrade linux-azure-5.4Upgrade linux-hweUpgrade linux-oracleUpgrade linux-gcp-fipsUpgrade linux-fipsUpgrade linux-gcp-5.4Upgrade linux-azureUpgrade linux-gcp-4.15Upgrade linux-gcpUpgrade linux-hwe-5.4Upgrade linux-aws-fipsUpgrade linux-gkeopUpgrade linux-azure-fipsUpgrade linux-kvmUpgrade linux-azure-4.15Upgrade linux-aws-hwe | Nov 19, 2024 | Feb 28, 2024 |
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub