VulnerabilityPublished 20 Jul 2026Updated 22 Oct 2026

CVE-2026-63932: Linux kernel · iio: chemical: mhz19b: reject oversized serial replies

Affects Linux kernelSource GCVE Database

Not known to be exploited · fixed in 7.0.0-28.28~24.04.1 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 7.0.0-28.28~24.04.1, 7.0.0-1016.16~24.04.1, 7.0.0-28.28 +12

Exploitation 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.

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 <7.0.0-28.28	Fixed in 7.0.0-28.28
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected <7.0.0-1009.9	Fixed in 7.0.0-1009.9
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected <7.0.0-1010.10	Fixed in 7.0.0-1010.10
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected <7.0.0-1009.9	Fixed in 7.0.0-1009.9
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected <7.0.0-1008.8	Fixed in 7.0.0-1008.8
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected <7.0.0-1003.4	Fixed in 7.0.0-1003.4

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 vendor advisory confirms that the issue has been fixed by rejecting oversized serial replies and resetting the reply state. Users should update to the fixed kernel versions as per their distribution's security notices. No additional mitigation is required beyond applying the official fix.

Description

A vulnerability in the Linux kernel's iio chemical mhz19b driver allowed oversized serial replies to overflow a fixed-size buffer, potentially leading to memory corruption. The issue was caused by the mhz19b_receive_buf() function appending serial data chunks without verifying buffer capacity. The flaw was fixed by rejecting oversized replies before copying and resetting the reply state before each command. This vulnerability affects multiple Linux kernel versions and has been addressed in official updates.

Impact

The vulnerability could lead to memory corruption within the kernel space, potentially causing system instability or enabling privilege escalation. However, no known exploits are reported in the wild. The impact is considered medium severity due to the possibility of kernel memory corruption.

Summary

CVE-2026-63932 describes a buffer overflow vulnerability in the Linux kernel's iio chemical mhz19b driver. The function mhz19b_receive_buf() appends each serial device chunk into a fixed-size receive buffer (MHZ19B_CMD_SIZE) and advances the buffer index without checking if the chunk fits in the remaining space. This can cause an overflow of the buffer before the command path validates the reply. The fix involves resetting the reply state before each command and rejecting oversized serial replies before copying them into the buffer, returning an error (-EMSGSIZE) and waking the waiting process instead of overwriting the buffer.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Oct 2026, 12:47 UTC

Technical details

References

Community reviews

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