CVE-2026-98021

In the Linux kernel, the following vulnerability has been resolved: net: reject oversized tx_queue_len at netlink parse time rtnl_create_link() assigns IFLA_TXQLEN directly to dev->tx_queue_len without going through netif_change_tx_queue_len(), so a device created with "ip link add ... txqueuelen 500000" bypasses the S16_MAX cap and still triggers the oversized ring allocations in pfifo_fast, tun and tap. The veth peer nest (rtnl_nla_parse_ifinfomsg()) and the RTM_NEWLINK-on-existing-device path reach the same sinks. Enforce the cap in ifla_policy instead: IFLA_TXQLEN becomes NLA_POLICY_FULL_RANGE(NLA_U32, &txqlen_range) with txqlen_range = { .min = 0, .max = S16_MAX }. All netlink consumers parse against this policy - rtnl_setlink(), rtnl_newlink() (create and change), and the veth peer nest - so every netlink path is capped at parse time and rejects the attribute with -ERANGE plus a proper "integer out of range" extack message before any device state is modified (the RTM_SETLINK half-application wart is gone with it). Document the bound in the rt-link.yaml netlink spec. Conditions to recreate the bug: - CONFIG_NET_SCHED=y, CONFIG_VETH=y, CONFIG_USER_NS=y, CONFIG_NET_NS=y. - Unprivileged user in a fresh user+net namespace (unshare -Urn): ip link add v0 txqueuelen 500000 type veth peer name v1 -> on the fixed kernel this is rejected with -ERANGE ("integer out of range" extack) instead of installing an oversized tx_queue_len that later inflates pfifo_fast/tun/tap ring allocations. - ip link set v0 txqueuelen 500000 is likewise rejected at parse time.

• https://git.kernel.org/stable/c/1aa9e143bf51405665a793d4cc925e1c4f0c5922
• https://git.kernel.org/stable/c/2fd0880f0272ec022906a05587fd91416ebecc38
• https://git.kernel.org/stable/c/45ca9f59b6c7ea70e0a17054902b8a556913db34
• https://git.kernel.org/stable/c/a638a2625aa83160a394abe8e8b2e524a80c771b

Published

Sep 25, 2026

Last Modified

Sep 25, 2026

Status

Received

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-98016In the Linux kernel, the following vulnerability has been re…
• CVE-2026-98017In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2026-98018In the Linux kernel, the following vulnerability has been re…
• CVE-2026-98019In the Linux kernel, the following vulnerability has been re…
• CVE-2026-9802A flaw was found in Keycloak. When revokeRefreshToken=true i…6.8
• CVE-2026-98020In the Linux kernel, the following vulnerability has been re…
• CVE-2026-98022In the Linux kernel, the following vulnerability has been re…
• CVE-2026-98023In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2026-98024In the Linux kernel, the following vulnerability has been re…
• CVE-2026-98025In the Linux kernel, the following vulnerability has been re…
• CVE-2026-98026In the Linux kernel, the following vulnerability has been re…
• CVE-2026-98027In the Linux kernel, the following vulnerability has been re…7