VulnerabilityPublished 7 Nov 2026

CVE-2026-99282: Linux kernel · net/sched: sch_teql: fix use-after-free on lower qdisc drop

Source GCVE Database

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Authoritative record:CVE-2026-99282· High

Not known to be exploited · fixed in fc55d92ae6a4b2e7d062cad6d4c67f6b061d9cde : patch Linux kernel soon.

Data as of 7 Nov 2026, 16:04 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in fc55d92ae6a4b2e7d062cad6d4c67f6b061d9cde, 2702ae318630787c640ec0d0403ffd9d95c43e9e, 782d6bb8f9b8e9d8591181662222bf74cd3ecf79

Exploitation evidence

Disclosed: evidence found.
CVE published 7 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 7 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-hh8x-8f55-7ggp

What to do

Upgrade Linux kernel to fc55d92ae6a4b2e7d062cad6d4c67f6b061d9cde, 2702ae318630787c640ec0d0403ffd9d95c43e9e or 782d6bb8f9b8e9d8591181662222bf74cd3ecf79.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 572a9d7b6fc7f20f573664063324c086be310c42, < fc55d92ae6a4b2e7d062cad6d4c67f6b061d9cde	Fixed in fc55d92ae6a4b2e7d062cad6d4c67f6b061d9cde
LinuxLinux	Affected ≥ 572a9d7b6fc7f20f573664063324c086be310c42, < 2702ae318630787c640ec0d0403ffd9d95c43e9e	Fixed in 2702ae318630787c640ec0d0403ffd9d95c43e9e
LinuxLinux	Affected ≥ 572a9d7b6fc7f20f573664063324c086be310c42, < 782d6bb8f9b8e9d8591181662222bf74cd3ecf79	Fixed in 782d6bb8f9b8e9d8591181662222bf74cd3ecf79
LinuxLinux	Affected =2.6.33	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel to address this use-after-free vulnerability. Users should update to a kernel version that includes this patch once available. Until then, avoiding the specific network configuration that triggers the bug (CONFIG_NET_SCH_TEQL, CONFIG_VLAN_8021Q, CONFIG_DUMMY with the described interface setup) may mitigate risk.

Description

A use-after-free vulnerability was identified and fixed in the Linux kernel's sch_teql network scheduler. The flaw occurs when the teql_master_xmit() function incorrectly handles the return value of a slave's ndo_start_xmit(), leading to use of a freed socket buffer (skb) after a lower queuing discipline (qdisc) drop. The fix involves improved checking of transmission completion status to prevent accessing freed memory.

Impact

This vulnerability could cause kernel memory corruption due to use-after-free, potentially leading to system instability or crashes. There is no indication of known exploitation in the wild. The impact is limited to systems with the affected kernel configuration and network setup involving sch_teql, VLAN, and dummy interfaces as described.

Summary

The vulnerability in the Linux kernel's net/sched subsystem relates to the sch_teql module. The function teql_master_xmit() only checked for NETDEV_TX_OK to determine if a packet was transmitted successfully. However, if a slave device consumed the skb but returned an error code such as NET_XMIT_DROP, the function mistakenly treated the skb as still owned, leading to use-after-free when it accessed the freed skb. This was particularly triggered when a VLAN slave returned NET_XMIT_DROP from dev_queue_xmit() after the skb was freed by the lower qdisc. The fix changes the logic to use dev_xmit_complete(), which correctly identifies consumed packets including those dropped by the lower qdisc, preventing use-after-free errors.

References

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