VulnerabilityPublished 28 Oct 2026

CVE-2026-99124: Linux kernel · s390/pci: Fix leak of uninitialized kernel data in SCLP report

Source GCVE Database

Authoritative record:CVE-2026-99124

Not known to be exploited · fixed in ba5001db9bb23ff7d2ea328c405c287ffb07786f : update Linux kernel when convenient.

Data as of 28 Oct 2026, 14:13 UTC

Severity

Low

Rated Low by Threat Radar's AI analysis · CVSS not yet scored by NVD

Patch: Available – fixed in ba5001db9bb23ff7d2ea328c405c287ffb07786f, 126a7c227d8543e13903dd5622640c1f0fcc5a16, 8ac60ae2a307a50b599bf5d300b448d638f3ba29

Exploitation evidence

Disclosed: evidence found.
CVE published 28 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-7c6q-xh8w-h79r

What to do

Upgrade Linux kernel to ba5001db9bb23ff7d2ea328c405c287ffb07786f, 126a7c227d8543e13903dd5622640c1f0fcc5a16 or 8ac60ae2a307a50b599bf5d300b448d638f3ba29.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 368704a65be8620df795ccbeb44e025dafbc3e1f, < ba5001db9bb23ff7d2ea328c405c287ffb07786f	Fixed in ba5001db9bb23ff7d2ea328c405c287ffb07786f
LinuxLinux	Affected ≥ 368704a65be8620df795ccbeb44e025dafbc3e1f, < 126a7c227d8543e13903dd5622640c1f0fcc5a16	Fixed in 126a7c227d8543e13903dd5622640c1f0fcc5a16
LinuxLinux	Affected ≥ 368704a65be8620df795ccbeb44e025dafbc3e1f, < 8ac60ae2a307a50b599bf5d300b448d638f3ba29	Fixed in 8ac60ae2a307a50b599bf5d300b448d638f3ba29
LinuxLinux	Affected =4.7	Fixed in–

AI-suggested

If you cannot patch yet, ensure that only trusted privileged entities can interact with the SCLP report processing to minimize risk.

Description

A vulnerability in the Linux kernel s390/pci subsystem allows leakage of uninitialized kernel data in SCLP error reports when user-space provides a short buffer. This causes an out-of-bounds read of up to around 4KB of kernel memory. The leak is limited to privileged entities that can already access the memory page containing the report, so it does not expose new data to unauthorized users. The issue results in malformed error reports that should be rejected.

Impact

This vulnerability causes an out-of-bounds read of uninitialized kernel memory, potentially leaking up to 4KB of kernel data. However, the data leak is limited to privileged entities that can already access the memory page containing the report, so it does not expose new sensitive information to unauthorized users. The malformed error report may cause processing issues but does not escalate privileges or allow unauthorized data access.

Summary

The Linux kernel s390/pci subsystem had a flaw in the report_error_write() function where it checked the buffer size only against the header struct size but not against the full report length claimed by report->length. If user-space supplied a buffer smaller than the claimed report length, an out-of-bounds read occurred, leaking up to approximately 4KB of uninitialized kernel memory allocated by kmalloc in kernfs_fop_write_iter(). The leak is constrained to privileged entities processing the SCLP report, which already have access to the memory page, thus limiting the impact to an out-of-bounds read and malformed error report generation.

References

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