{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-98299 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-98299 is a denial of service vulnerability in Linux, published on 6 Oct 2026. An attacker needs administrator access to exploit it, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-98299 and fix it if it is affected.\n\nWhat it is: CVE-2026-98299 is a denial of service vulnerability in Linux, published on 6 Oct 2026. An attacker needs administrator access to exploit it, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-98299 in the wild and no public exploit code.\n\nAffected product: Linux. 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-2026-98299/ (Markdown: https://insights.sbomify.com/CVE-2026-98299/index.md)","id":"CVE-2026-98299","markdown":"https://insights.sbomify.com/CVE-2026-98299/index.md","name":"CVE-2026-98299","record":{"aliases":["AZL-106307","BELL-CVE-2026-98299","DEBIAN-CVE-2026-98299","GHSA-3ffw-pmr7-c5jp","UBUNTU-CVE-2026-98299"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":true,"product_category":"Linux kernel TCP","requires_auth":"high_privilege","summary":"A local attacker with high privileges can cause a kernel crash by setting the TCP receive buffer size to an extremely low value, triggering a division by zero error.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: do not let tcp_rmem be set below 4096\n\nWe can hit a division by zero crash in tcp_rcvbuf_grow()\nand tcp_rcv_space_adjust():\n\ndivide error: 0000 [#1] PREEMPT SMP\nRIP: 0010:tcp_rcvbuf_grow+0x187/0x450 net/ipv4/tcp_input.c:939\n...\ngrow = div_u64(((u64)rcvwin \u003c\u003c 1) * (newval - oldval), oldval);\n\nThe division uses oldval = tp-\u003ercvq_space.space as divisor.\nWhen tp-\u003ercvq_space.space is zero, this leads to a divide-by-zero\nexception.\n\ntp-\u003ercvq_space.space is initialized in tcp_init_buffer_space():\n    tp-\u003ercvq_space.space = min3(tp-\u003ercv_ssthresh, tp-\u003ercv_wnd,\n                                (u32)TCP_INIT_CWND * tp-\u003eadvmss);\n\nIf tcp_rmem[1] is configured to very small values (such as 1),\nsk-\u003esk_rcvbuf is initialized to 1. Then tcp_full_space(sk), which\ncomputes (sk-\u003esk_rcvbuf * scaling_ratio) \u003e\u003e 8, truncates to 0.\nThis sets tp-\u003ewindow_clamp = 0, tp-\u003ercv_ssthresh = 0, and\ntp-\u003ercvq_space.space = 0. Later, when data arrives and DRS is invoked,\ntcp_rcvbuf_grow() divides by oldval == 0.\n\nBack in 2015, commit b1cb59cf2efe (\"net: sysctl_net_core: check SNDBUF\nand RCVBUF for min length\") ensured that net.core.rmem_default and\nnet.core.rmem_max cannot be set below SOCK_MIN_RCVBUF. Similarly,\nSO_RCVBUF setsockopt enforces max_t(int, val * 2, SOCK_MIN_RCVBUF).\n\nHowever, net.ipv4.tcp_rmem still had .extra1 = SYSCTL_ONE, allowing\narbitrarily small values.\n\nBecause SOCK_MIN_RCVBUF depends on sizeof(struct sk_buff) and cacheline\nalignment, its value varies across architectures and configuration options.\nUsing a fixed constant of 4096 ensures a predictable, architecture-\nindependent lower bound that is safely above SOCK_MIN_RCVBUF everywhere\nand matches the documented 4K default.\n\nFix this by setting tcp_rmem.extra1 to 4096 and updating the documentation.","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":"tcp: do not let tcp_rmem be set below 4096","id":"CVE-2026-98299","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":0,"n_references":8,"next":{"headline":"tcp: Don't call skb_clone_and_charge_r() for close()d listener in tcp_v6_do_rcv().","id":"CVE-2026-98300"},"packages":[],"prev":{"headline":"dmaengine: mmp_pdma: fix wrong sg length in mmp_pdma_prep_slave_sg()","id":"CVE-2026-98298"},"products":["Linux"],"published":"2026-10-06","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-19","vendors":["Linux"]},"summary":"A local attacker with high privileges can cause a kernel crash by setting the TCP receive buffer size to an extremely low value, triggering a division by zero error.","url":"https://insights.sbomify.com/CVE-2026-98299/"}