VulnerabilityPublished 17 Sep 2026Updated 20 Oct 2026

CVE-2026-93048: Linux kernel · mtd: part: reject MTDPART_OFS_RETAIN in mtd_add_partition()

Affects Linux kernelSource GCVE Database

Authoritative record:CVE-2026-93048· Medium

Not known to be exploited.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 17 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.

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.

microsoft-security-response-ce

What to do

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 fix is available that updates the mtd_add_partition() function to reject the MTDPART_OFS_RETAIN offset, consistent with other special offsets. Users should apply the official Linux kernel updates that include this patch to resolve the issue. No additional mitigations are indicated by the vendor advisory.

Description

A vulnerability in the Linux kernel's mtd_add_partition() function allows improper handling of the special offset value MTDPART_OFS_RETAIN (-3). This leads to a WARN_ON condition due to erasesize being set to zero or a disabled empty partition being created, causing undefined behavior when adding MTD partitions via the BLKPG ioctl on NAND devices. The issue arises because MTDPART_OFS_RETAIN was not rejected in dynamic partition paths, unlike other special offsets. The flaw has been fixed by updating mtd_add_partition() to reject MTDPART_OFS_RETAIN consistently.

Impact

The vulnerability causes undefined behavior in the Linux kernel's MTD subsystem when adding partitions via BLKPG ioctl on NAND devices. This can trigger kernel warnings (WARN_ON) and result in invalid or disabled partitions being created. While it does not directly cause code execution or data corruption, it may affect system stability or partition management reliability on affected systems.

Summary

The Linux kernel vulnerability involves the mtd_add_partition() function not rejecting the special offset MTDPART_OFS_RETAIN (-3). This offset depends on cur_offset being the end of the previous partition, but in dynamic partitioning, cur_offset equals the offset argument itself, causing an underflow in partition size calculation. This underflow can lead to erasesize being zero, triggering a WARN_ON in add_mtd_device(), or result in a disabled empty partition instead of an error. The root cause is that MTDPART_OFS_RETAIN was added for static partition tables without updating mtd_add_partition() to reject it, unlike MTDPART_OFS_APPEND and MTDPART_OFS_NXTBLK. The fix adds MTDPART_OFS_RETAIN to the rejection list in mtd_add_partition(), preventing this undefined behavior.

GCVE source: db.gcve.eu
OSV ID: UBUNTU-CVE-2026-93048
Osv Schema Version: 1.7.0
Ecosystems: Ubuntu:Pro:14.04:LTS, Ubuntu:Pro:16.04:LTS, Ubuntu:16.04:LTS, Ubuntu:Pro:FIPS:16.04:LTS, Ubuntu:Pro:18.04:LTS, Ubuntu:18.04:LTS, Ubuntu:Pro:FIPS-updates:18.04:LTS, Ubuntu:Pro:FIPS:18.04:LTS, Ubuntu:Pro:20.04:LTS, Ubuntu:20.04:LTS, Ubuntu:Pro:FIPS-updates:20.04:LTS, Ubuntu:Pro:FIPS:20.04:LTS, Ubuntu:22.04:LTS, Ubuntu:Nvidia-BlueField:22.04:LTS, Ubuntu:Pro:FIPS-preview:22.04:LTS, Ubuntu:Pro:FIPS-updates:22.04:LTS, Ubuntu:Pro:Realtime:22.04:LTS, Ubuntu:24.04:LTS, Ubuntu:Nvidia-BlueField:24.04:LTS, Ubuntu:Pro:FIPS-updates:24.04:LTS, Ubuntu:Pro:Realtime:24.04:LTS, Ubuntu:26.04:LTS

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 24 Oct 2026, 23:14 UTC

Technical details

References

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