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Double-free in Linux kernel net/sched teql_master_xmit

IdentifiersCVE-2026-23449CWE-415· Double Free

CVE-2026-23449 is a Linux kernel vulnerability in the traffic equalizer scheduler (TEQL) code under net/sched. The flaw is described as a double-free in the TEQL transmit path, triggered when a TEQL device uses a lockless Qdisc as its root qdisc. In that configuration, qdisc_reset was not performed under seq_lock, allowing a race with the datapath. That race can result in the same skb data being freed twice, as reflected by KASAN reports showing a double-free in skb_release_data(), with execution involving qdisc_reset(), teql_destroy(), and qdisc_graft(). The upstream fix is to call qdisc_reset while holding seq_lock so teardown/reset cannot race with concurrent packet processing.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can corrupt kernel memory and crash the system. The observed manifestation is a kernel double-free in skb handling, which can lead to denial of service via kernel panic/oops. Because this is a kernel memory-management flaw, it may also have broader confidentiality, integrity, and availability consequences depending on exploitability in a given environment, but the provided material specifically evidences crash and memory corruption conditions.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by avoiding use of TEQL devices with a lockless root Qdisc configuration until a fixed kernel is deployed. More generally, disable or avoid the TEQL scheduler where it is not required. There is no complete mitigation in the provided material short of running a kernel containing the seq_lock-based fix.

Remediation

Patch, then assume compromise.

Apply a kernel update that includes the upstream fix for CVE-2026-23449 in net/sched/teql. The fix ensures qdisc_reset is invoked while holding seq_lock when a TEQL device has a lockless root Qdisc, preventing races with the datapath. Vendor advisories indicate patched kernels are available across multiple SUSE product lines; administrators should install the relevant kernel package update and reboot into the fixed kernel.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

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VendorProductType
LinuxLinux Kerneloperating_system

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