CVE-2026-64012: Linux kernel · net/sched: sch_sfb: Replace direct dequeue call with peek and qdisc_dequeue_peeked
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1117.124~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +65
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 20 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and should be applied to affected Linux kernel versions. The fix replaces the direct dequeue call with the qdisc_dequeue_peeked() method to prevent kernel panic. Users should update their Linux kernel to a version including this fix as indicated by their distribution's security advisory.
Description
A vulnerability in the Linux kernel's network scheduler (net/sched) subsystem, specifically in the sch_sfb queuing discipline, could cause a kernel panic when sfb has child qdiscs such as qfq. The issue arises from a direct dequeue call instead of using the appropriate peek and dequeue method, leading to a null pointer dereference. This flaw has been fixed by replacing the direct dequeue call with the qdisc_dequeue_peeked() method to properly handle skb retrieval from child qdiscs.
References
- nvd.nist.gov/vuln/detail/CVE-2026-64012 (opens in a new tab)
- git.kernel.org/stable/c/1b9bc71153b01dbde8045b9edede4240f4f5520e (opens in a new tab)
- git.kernel.org/stable/c/1e70274d3b81de28973bcdbce40a512bcb181ff9 (opens in a new tab)
- git.kernel.org/stable/c/6c153d97c100f5b282c424101d8ff63122306997 (opens in a new tab)
- git.kernel.org/stable/c/84bfbfc0c48731bcce74cdf4f9c497547ec525e0 (opens in a new tab)
- git.kernel.org/stable/c/9ad3288632c859cf84183199832d822e7a70bdae (opens in a new tab)
- git.kernel.org/stable/c/dbc560858da8b77dd9e4ef0cd93d421e0e4d7e0e (opens in a new tab)
- git.kernel.org/stable/c/e125f5980b730c67c92a30cf150ec8c3d6777318 (opens in a new tab)
- git.kernel.org/stable/c/e5ea51e5f3fbba41d50cd84a530f33bc1c8f4d57 (opens in a new tab)
- ubuntu.com/security/CVE-2026-64012 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64012 (opens in a new tab)
- git.kernel.org/linus/1b9bc71153b01dbde8045b9edede4240f4f5520e (opens in a new tab)
- ubuntu.com/security/notices/USN-8593-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8603-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8618-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8663-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8664-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8903-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8905-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8906-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8904-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8903-2 (opens in a new tab)