{ "document": { "category": "csaf_security_advisory", "csaf_version": "2.0", "distribution": { "tlp": { "label": "WHITE", "url": "https://www.first.org/tlp/" } }, "lang": "en", "notes": [ { "category": "summary", "text": "On 2026-10-29, the Go security team reported a demonstrated attack that ran code remotely through CVE-2026-98432. The attack used Multipath TCP (MPTCP) connections, which programs built with Go 1.24 or later accept by default. The Go team states that the bug is not specific to MPTCP, so a kernel update is necessary to fix it.\n\nGravwell builds current releases with Go 1.26, so Gravwell components that listen for connections accept MPTCP by default. Every Linux host that runs Gravwell on a vulnerable kernel is affected.", "title": "Summary" }, { "category": "general", "text": "Do these steps on each Linux host that runs Gravwell services or ingesters:\n\n1. Install the kernel update for CVE-2026-98432 from the vendor of your operating system. On Debian 13, the fixed version is linux 6.12.113-1.\n2. Reboot the host. The fixed kernel runs only after a reboot.\n3. Make sure that uname -r shows the fixed kernel version.\n\nIf you run Gravwell in Docker, do these steps on the Docker host. Containers use the kernel of their host.", "title": "Self-Hosted" }, { "category": "general", "text": "No action required from users of Gravwell Cloud services.\n\nIf you run edge-deployed ingesters or federators on your own hosts, do the Self-Hosted steps on those hosts.", "title": "Gravwell Cloud" }, { "category": "legal_disclaimer", "text": "This advisory is provided as is. Scores are Gravwell's assessment of each vulnerability as it affects Gravwell.", "title": "Terms of use" } ], "publisher": { "category": "vendor", "contact_details": "security@gravwell.io", "name": "Gravwell", "namespace": "https://gravwell.io" }, "references": [ { "category": "self", "summary": "Canonical URL", "url": "https://security.gravwell.io/.well-known/csaf/white/2026/gsa-2026-0003.json" }, { "category": "self", "summary": "Human-readable advisory", "url": "https://security.gravwell.io/advisories/GSA-2026-0003/" } ], "title": "Use-after-free in the Linux kernel during IPv4 TCP connection setup", "tracking": { "current_release_date": "2026-10-30T00:00:00.000Z", "generator": { "engine": { "name": "gsa" } }, "id": "GSA-2026-0003", "initial_release_date": "2026-10-30T00:00:00.000Z", "revision_history": [ { "date": "2026-10-30T00:00:00.000Z", "number": "1", "summary": "Initial publication." } ], "status": "interim", "version": "1" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:semver/*", "product": { "name": "Gravwell (all versions)", "product_id": "GRAVWELL-ALL" } } ], "category": "product_name", "name": "Gravwell" } ], "category": "vendor", "name": "Gravwell" } ] }, "vulnerabilities": [ { "cve": "CVE-2026-98432", "cwe": { "id": "CWE-416", "name": "Use After Free" }, "notes": [ { "category": "description", "text": "CVE-2026-98432 is a use-after-free in the Linux kernel during IPv4 TCP connection setup. An attacker on the network can trigger the bug without credentials. It affects kernels from 4.4 up to the stable releases that contain the fix.", "title": "Description" }, { "category": "details", "text": "The Linux kernel on hosts that run Gravwell services or ingesters", "title": "Affected component" }, { "category": "other", "text": "CVSS 4.0 base score 9.3 (Critical), CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N", "title": "CVSS 4.0" } ], "product_status": { "known_affected": [ "GRAVWELL-ALL" ] }, "references": [ { "category": "external", "summary": "CVE record: CVE-2026-98432", "url": "https://www.cve.org/CVERecord?id=CVE-2026-98432" }, { "category": "external", "summary": "NVD: CVE-2026-98432", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98432" }, { "category": "external", "summary": "Debian security tracker: CVE-2026-98432", "url": "https://security-tracker.debian.org/tracker/CVE-2026-98432" }, { "category": "external", "summary": "oss-security: Go announcement of the MPTCP exploit", "url": "https://www.openwall.com/lists/oss-security/2026/10/30/1" }, { "category": "external", "summary": "Go Issue #82717", "url": "https://go.dev/issue/82717" } ], "remediations": [ { "category": "workaround", "details": "Do these steps on each Linux host that runs Gravwell services or ingesters:\n\n1. Install the kernel update for CVE-2026-98432 from the vendor of your operating system. On Debian 13, the fixed version is linux 6.12.113-1.\n2. Reboot the host. The fixed kernel runs only after a reboot.\n3. Make sure that uname -r shows the fixed kernel version.\n\nIf you run Gravwell in Docker, do these steps on the Docker host. Containers use the kernel of their host.", "product_ids": [ "GRAVWELL-ALL" ], "url": "https://security.gravwell.io/advisories/GSA-2026-0003/" }, { "category": "mitigation", "details": "If you cannot reboot a host soon, run these commands on that host. They disable MPTCP and restart the Gravwell services.\n\nsudo sysctl -w net.mptcp.enabled=0\nsudo systemctl restart 'gravwell_*'\n\nThe restart is necessary because a listener that is already open keeps MPTCP until its service restarts.\n\nIf a Gravwell container does not use --network host, start it with --sysctl net.mptcp.enabled=0. Such a container has its own network stack. The host setting does not apply to it.\n\nThis setting blocks only the demonstrated attack. It does not fix the kernel bug.", "product_ids": [ "GRAVWELL-ALL" ] } ], "scores": [ { "cvss_v3": { "baseScore": 9.8, "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1" }, "products": [ "GRAVWELL-ALL" ] } ], "title": "Use-after-free in the Linux kernel during IPv4 TCP connection setup" } ] }