VulnerabilityPublished 18 Oct 2026

CVE-2026-98747: Linux kernel · serial: core: fix NULL pointer dereference in serial_core_unregister_port()

Source GCVE Database

Authoritative record:CVE-2026-98747· Medium

Not known to be exploited : upgrade to 499485a67fbacf4d9afbdb43522388c64f853428 or 54abbb862366dcaf1f22f1e968358147b7d0547d when convenient.

Data as of 26 Oct 2026, 12:55 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 499485a67fbacf4d9afbdb43522388c64f853428, 54abbb862366dcaf1f22f1e968358147b7d0547d

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 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.

ghsa-6854-f26p-xx8r

What to do

Upgrade Linux kernel to 499485a67fbacf4d9afbdb43522388c64f853428 or 54abbb862366dcaf1f22f1e968358147b7d0547d.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 84a9582fd203063cd4d301204971ff2cd8327f1a, < 499485a67fbacf4d9afbdb43522388c64f853428	Fixed in 499485a67fbacf4d9afbdb43522388c64f853428
LinuxLinux	Affected ≥ 84a9582fd203063cd4d301204971ff2cd8327f1a, < 54abbb862366dcaf1f22f1e968358147b7d0547d	Fixed in 54abbb862366dcaf1f22f1e968358147b7d0547d
LinuxLinux	Affected =6.5	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel to address this issue by adding checks for NULL pointers and proper synchronization. Users should apply the official kernel updates containing this fix. No additional mitigations are indicated.

Description

A NULL pointer dereference vulnerability in the Linux kernel's serial core subsystem was resolved. The issue occurs in the function serial_core_unregister_port() when port->port_dev is NULL, leading to a potential kernel crash. The flaw arises because port->port_dev can be cleared on teardown or never set if registration fails, but the function attempts to dereference it without checking. The fix involves returning early if no port device is present and ensuring proper synchronization with port_mutex. Additionally, port->port_dev is cleared on error paths during registration to prevent this condition.

Impact

This vulnerability can cause a kernel NULL pointer dereference, leading to a denial of service via kernel crash. There is no indication of privilege escalation or code execution. The impact is limited to system stability and availability.

Summary

The vulnerability in the Linux kernel's serial core involves a NULL pointer dereference in serial_core_unregister_port(). Specifically, port->port_dev can be NULL if no port device is installed or if registration failed before serial_core_port_device_add(). The function serial_core_unregister_port() calls serial_core_get_ctrl_dev() with this NULL pointer, causing a kernel NULL pointer dereference detected by KASAN. The patch adds an early return when port->port_dev is NULL and ensures port->port_dev is read under port_mutex. It also clears port->port_dev on error paths during registration to prevent stale pointers.

References

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