{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-46912 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-46912 is a high-severity vulnerability in Linux kernel, published on 27 Feb 2024. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-46912 and fix it if it is affected.\n\nWhat it is: CVE-2021-46912 is a high-severity vulnerability in Linux kernel, published on 27 Feb 2024. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-46912 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-46912/ (Markdown: https://insights.sbomify.com/CVE-2021-46912/index.md)","id":"CVE-2021-46912","markdown":"https://insights.sbomify.com/CVE-2021-46912/index.md","name":"CVE-2021-46912","record":{"aliases":["DEBIAN-CVE-2021-46912","GHSA-gpxm-mp2h-x3pp","UBUNTU-CVE-2021-46912"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["data_read"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A Linux kernel vulnerability allows writing to a global sysctl in one network namespace to leak configuration into others, enabling information disclosure.","user_interaction":"not_required","vuln_class":"information_disclosure"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.3,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L","version":"3.1"},"cwes":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: Make tcp_allowed_congestion_control readonly in non-init netns\n\nCurrently, tcp_allowed_congestion_control is global and writable;\nwriting to it in any net namespace will leak into all other net\nnamespaces.\n\ntcp_available_congestion_control and tcp_allowed_congestion_control are\nthe only sysctls in ipv4_net_table (the per-netns sysctl table) with a\nNULL data pointer; their handlers (proc_tcp_available_congestion_control\nand proc_allowed_congestion_control) have no other way of referencing a\nstruct net. Thus, they operate globally.\n\nBecause ipv4_net_table does not use designated initializers, there is no\neasy way to fix up this one \"bad\" table entry. However, the data pointer\nupdating logic shouldn't be applied to NULL pointers anyway, so we\ninstead force these entries to be read-only.\n\nThese sysctls used to exist in ipv4_table (init-net only), but they were\nmoved to the per-net ipv4_net_table, presumably without realizing that\ntcp_allowed_congestion_control was writable and thus introduced a leak.\n\nBecause the intent of that commit was only to know (i.e. read) \"which\ncongestion algorithms are available or allowed\", this read-only solution\nshould be sufficient.\n\nThe logic added in recent commit\n31c4d2f160eb: (\"net: Ensure net namespace isolation of sysctls\")\ndoes not and cannot check for NULL data pointers, because\nother table entries (e.g. /proc/sys/net/netfilter/nf_log/) have\n.data=NULL but use other methods (.extra2) to access the struct net.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"net: Make tcp_allowed_congestion_control readonly in non-init netns","id":"CVE-2021-46912","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"information_disclosure","year":"2021"},"n_packages":0,"n_references":3,"next":{"headline":"netfilter: nftables: clone set element expression template","id":"CVE-2021-46913"},"packages":[],"prev":{"headline":"ch_ktls: Fix kernel panic","id":"CVE-2021-46911"},"products":["Linux"],"published":"2024-02-27","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"A Linux kernel vulnerability allows writing to a global sysctl in one network namespace to leak configuration into others, enabling information disclosure.","url":"https://insights.sbomify.com/CVE-2021-46912/"}