CVE-2021-47010
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.26%). 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: 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 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.26% probability · 17th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-400
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/6c1ea8bee75df8fe2184a50fcd0f70bf82986f42Patch
- https://git.kernel.org/stable/c/8d432592f30fcc34ef5a10aac4887b4897884493Patch
- https://git.kernel.org/stable/c/9884f745108f7d25b189bbcd6754e284fb29ab68Patch
- https://git.kernel.org/stable/c/992de06308d9a9584d59b96d294ac676f924e437Patch
- https://git.kernel.org/stable/c/e7d7bedd507bb732e600403b7a96f9fe48d0ca31Patch
- https://git.kernel.org/stable/c/efe1532a6e1a8e3c343d04fff510f0ed80328f9cPatch
- https://git.kernel.org/stable/c/6c1ea8bee75df8fe2184a50fcd0f70bf82986f42Patch
- https://git.kernel.org/stable/c/8d432592f30fcc34ef5a10aac4887b4897884493Patch
- https://git.kernel.org/stable/c/9884f745108f7d25b189bbcd6754e284fb29ab68Patch
- https://git.kernel.org/stable/c/992de06308d9a9584d59b96d294ac676f924e437Patch
- https://git.kernel.org/stable/c/e7d7bedd507bb732e600403b7a96f9fe48d0ca31Patch
- https://git.kernel.org/stable/c/efe1532a6e1a8e3c343d04fff510f0ed80328f9cPatch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.