CVE-2026-98061: Linux kernel · bpf: Reject tail calls directly from callback frames
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 12:30 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 25 Sep 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
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 fix has been implemented in the Linux kernel to reject tail calls made directly from callback frames before the verifier constructs an inconsistent return state. Users should update to a kernel version that includes this fix. Since this is a kernel-level vulnerability, applying the official kernel update or patch from the vendor is the recommended remediation.
Description
A vulnerability in the Linux kernel's BPF subsystem allows a CAP_BPF task to trigger a kernel warning and an error during BPF program loading by making tail calls directly from callback frames. This issue arises because the verifier encounters an inconsistent return state when processing such tail calls. The vulnerability has been resolved by rejecting tail calls made directly by callbacks before the inconsistent state is constructed.
References
- ubuntu.com/security/CVE-2026-98061 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98061 (opens in a new tab)
- git.kernel.org/stable/c/96d31b28263c429a56e4de85bcf744a5c320b3a3 (opens in a new tab)
- git.kernel.org/stable/c/617c8266e49f45747f71e74177646a63f72b7025 (opens in a new tab)
- git.kernel.org/stable/c/266aa4ad0b2e82397cd9045752c9bff03d98eddd (opens in a new tab)