CVE-2026-74701: Linux kernel · net/openvswitch: check Ethernet header length in key_extract()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
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 +27
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation 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 and should be applied to affected Linux Azure kernel versions to resolve this vulnerability. The fix involves adding a check on the Ethernet header length before accessing it in key_extract(). Users should update their systems to the patched kernel versions listed in the advisory. No additional mitigation steps are indicated by the vendor advisory.
Description
A vulnerability in the Linux kernel's Open vSwitch (OVS) component was resolved that involved improper checking of Ethernet header length in the key_extract() function. When packets arrive on ARPHRD_NONE devices such as TUN, the kernel trusted a user-provided protocol field without verifying sufficient linear data length, potentially causing a kernel BUG due to out-of-bounds memory access. This flaw could lead to system crashes or denial of service. The issue was fixed by adding a check on the Ethernet header before accessing it. Several specific Linux Azure kernel versions are affected. A patch is available to address this vulnerability.
References
- nvd.nist.gov/vuln/detail/CVE-2026-74701 (opens in a new tab)
- git.kernel.org/stable/c/0b60b55652ba772b173dddc63f3851e1d2dd5927 (opens in a new tab)
- git.kernel.org/stable/c/81f9b09f0ea3ba9ab966dd17e9f32625a14555e9 (opens in a new tab)
- git.kernel.org/stable/c/831471718f6e19aed1a330b03b53190a90e06466 (opens in a new tab)
- git.kernel.org/stable/c/9b8cfbb58b85bfa7a78fac47fdc77396cd01f699 (opens in a new tab)
- git.kernel.org/stable/c/a8139285c8925efe59af28a9169bb2fda91bff15 (opens in a new tab)
- git.kernel.org/stable/c/cf6f8b29befb92173659bcef6a441d274947bfae (opens in a new tab)
- git.kernel.org/stable/c/d8bea341b183190ce6c055ab0e64ab78eb9a7290 (opens in a new tab)
- git.kernel.org/stable/c/e85278afd4890dd190ba3c7a1b1a712b801c9fe1 (opens in a new tab)
- ubuntu.com/security/CVE-2026-74701 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-74701 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74701.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-8886-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-2 (opens in a new tab)