CVE-2026-74620: Linux kernel · net/sched: act_gact, act_police: range check the fallback control action
Affects Linux kernelSource GCVE Database
Not known to be exploited · fixed in 5.15.0-1117.124~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% 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 +26
Exploitation evidence
Disclosed: evidence found.
CVE published 22 Aug 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 that corrects the validation of fallback control actions in the Linux kernel net/sched subsystem. Systems should be updated to a fixed kernel version as provided by the vendor. The Ubuntu advisory USN-8878-1 confirms that this issue is fixed in updated kernel packages. No additional mitigation is required once the patch is applied.
Description
A vulnerability in the Linux kernel's network scheduler (net/sched) involving the act_gact and act_police modules allows user space to set an out-of-range fallback control action verdict (TC_ACT_CONSUMED) that causes a memory leak of sk_buff objects for every packet processed. This issue was introduced after the addition of TC_ACT_CONSUMED, which was not properly range-checked in fallback control actions, leading to unbounded memory leaks. The flaw has been fixed by improving validation of fallback control actions to reject invalid verdicts.
References
- nvd.nist.gov/vuln/detail/CVE-2026-74620 (opens in a new tab)
- git.kernel.org/stable/c/2e8df8c9190335475a3b64a159d3efd8cdd1cb73 (opens in a new tab)
- git.kernel.org/stable/c/5344e01179baa37547ab29fd7b8614f83faa190c (opens in a new tab)
- git.kernel.org/stable/c/6bcb8839aa2d686964a4154650afc4db91e1c514 (opens in a new tab)
- git.kernel.org/stable/c/725efc2ab4a40affc4e285a2dc4896d103948a6c (opens in a new tab)
- git.kernel.org/stable/c/883b56ae58fe657d8497806c7059646e9ba6dbd0 (opens in a new tab)
- git.kernel.org/stable/c/92f00f1d4d204a428b38e26fce3baee144b6955d (opens in a new tab)
- git.kernel.org/stable/c/efa58aeb6a99028b1fbc3ab2f31ba3a881211ad4 (opens in a new tab)
- ubuntu.com/security/CVE-2026-74620 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-74620 (opens in a new tab)
- git.kernel.org/linus/883b56ae58fe657d8497806c7059646e9ba6dbd0 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74620.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (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-8875-2 (opens in a new tab)