VulnerabilityPublished 19 Jul 2026

CVE-2026-63949: Linux kernel · auxdisplay: line-display: fix OOB read on zero-length message_store()

Source GCVE Database

Not known to be exploited.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 19 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.

ghsa-3qfr-7vgq-2884

What to do

AI-suggested

A fix is available that adds a check on the count variable before accessing msg[count - 1] in linedisp_display(). Users should apply the official Linux kernel patch that guards the trailing-newline trim with a count check. Until patched, avoid writing zero-length messages to the message sysfs attribute of affected auxdisplay drivers. Monitor vendor advisories for the official patch and update accordingly.

Description

A vulnerability in the Linux kernel auxdisplay line-display driver allows an out-of-bounds (OOB) read when writing zero-length messages to the message sysfs attribute. The function linedisp_display() reads msg[count - 1] without checking if count is zero, causing an OOB read at msg[-1]. This can lead to kernel memory being read incorrectly and potential kernel panic on KASAN-enabled kernels. The issue affects auxdisplay drivers registered via linedisp_register() or linedisp_attach(), including ht16k33, max6959, img-ascii-lcd, and seg-led-gpio. The vulnerability is triggered by zero-byte writes from userspace. A fix involves adding a count check before trimming the trailing newline in linedisp_display().

Impact

This vulnerability can cause out-of-bounds memory reads in the kernel, potentially leading to kernel panics on KASAN-enabled systems or undefined behavior on standard kernels. It may allow reading unintended kernel memory adjacent to the allocated buffer. There is no indication of privilege escalation or remote code execution from the provided data. The vulnerability is triggered by zero-byte writes to a sysfs attribute, which requires local access.

References

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