VulnerabilityPublished 22 Aug 2026Updated 9 Oct 2026

CVE-2026-74694: Linux kernel · net/ncsi: fix heap OOB read in NCSI_CMD_SEND_CMD payload length

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

Severity

Medium

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.

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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected 6.17.0-5.5 – 7.0.0-38.38 23 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected 6.17.0-1003.3 – 7.0.0-1017.17 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected 7.0.0-1003.3 – 7.0.0-1016.16 9 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 13 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected 7.0.0-1002.3 – 7.0.0-1008.9 6 affected builds	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 fixes the vulnerability by validating that the declared payload length does not exceed the actual netlink attribute data size, preventing out-of-bounds reads. Users should apply the official Linux kernel updates provided by their distribution, such as the Ubuntu security notice USN-8878-1. After updating, a system reboot is required to apply the fix. No additional mitigation is necessary as the issue is resolved by the patch.

Description

A heap out-of-bounds read vulnerability in the Linux kernel's Network Controller Sideband Interface (NCSI) driver was fixed. The flaw occurs when the payload length field in an NCSI command is larger than the actual netlink attribute data, leading to reading beyond the buffer and leaking kernel heap memory. This vulnerability requires CAP_NET_ADMIN privileges and affects systems with registered NCSI devices, such as OpenBMC on Aspeed BMC SoCs. The issue was discovered by Tencent Yunding Lab's dynamic kernel fuzzer and has been patched in affected Linux kernel versions.

Impact

An attacker with CAP_NET_ADMIN privileges on a system with a registered NCSI device can exploit this vulnerability to read beyond the intended buffer, leaking sensitive kernel heap memory contents. This information leak could potentially aid further attacks but does not directly allow code execution or privilege escalation. The vulnerability affects Linux kernel versions with the vulnerable net/ncsi implementation, commonly present in environments like OpenBMC on Aspeed BMC SoCs.

Summary

CVE-2026-74694 is a heap out-of-bounds read vulnerability in the Linux kernel's net/ncsi subsystem. The function ncsi_send_cmd_nl() copies data based on an attacker-controlled length field in the NCSI packet header without cross-checking against the actual netlink attribute payload size. This allows an attacker with CAP_NET_ADMIN privileges on systems with NCSI devices to leak up to approximately 64KB of kernel heap memory. The vulnerability does not cause a write overflow but results in an information leak. The flaw was identified by the autokbug dynamic kernel fuzzer at Tencent Yunding Lab and has been fixed by rejecting commands with payload lengths exceeding the attribute data size.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Oct 2026, 05:37 UTC

Technical details

References

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