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CVE Record

CVE-2024-26998: serial: core: Clearing the circular buffer before NULLifying it

In the Linux kernel, the following vulnerability has been resolved: serial: core: Clearing the circular buffer before NULLifying it The circular buffer is NULLified in uart_tty_port_shutdown() under the spin lock. However, the PM or other timer based callbacks may still trigger after this event without knowning that buffer pointer is not valid. Since the serial code is a bit inconsistent in checking the buffer state (some rely on the head-tail positions, some on the buffer pointer), it's better to have both aligned, i.e. buffer pointer to be NULL and head-tail possitions to be the same, meaning it's empty. This will prevent asynchronous calls to dereference NULL pointer as reported recently in 8250 case: BUG: kernel NULL pointer dereference, address: 00000cf5 Workqueue: pm pm_runtime_work EIP: serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809) ... ? serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809) __start_tx (drivers/tty/serial/8250/8250_port.c:1551) serial8250_start_tx (drivers/tty/serial/8250/8250_port.c:1654) serial_port_runtime_suspend (include/linux/serial_core.h:667 drivers/tty/serial/serial_port.c:63) __rpm_callback (drivers/base/power/runtime.c:393) ? serial_port_remove (drivers/tty/serial/serial_port.c:50) rpm_suspend (drivers/base/power/runtime.c:447) The proposed change will prevent ->start_tx() to be called during suspend on shut down port.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2024-26998 is a Linux kernel serial-driver bug that can cause a kernel crash when power-management or timer callbacks touch a serial transmit buffer after shutdown. The public record describes a NULL pointer dereference, not data theft or remote code execution. Business urgency depends on whether exposed systems run affected Linux kernels and serial/8250 paths.

Executive priority

Handle through normal kernel patch management, with higher priority for reliability-sensitive or embedded systems using serial hardware. There is no cited evidence of active exploitation, but kernel crashes can still affect uptime and operational resilience.

Technical view

The serial core NULLifies a circular buffer in uart_tty_port_shutdown() while asynchronous PM callbacks may still run. Some serial paths checked buffer positions rather than the pointer, allowing serial8250_tx_chars() to dereference NULL during runtime suspend. The fix aligns buffer pointer and head/tail state so shutdown ports are treated as empty before callbacks can start transmission.

Likely exposure

Exposure is most relevant to Linux systems using affected kernel builds and serial/8250 runtime power-management paths. The provided source data lists Linux as affected but gives no CPEs or environmental prerequisites beyond the serial-core behavior. Distribution kernels may carry backported fixes, so version-only checks need vendor confirmation.

Exploitation context

The bundle does not show KEV listing, public exploitation, exploit code, or remote attack evidence. The described impact is a kernel NULL pointer dereference observed in a power-management workqueue. Treat this primarily as an availability and stability issue unless vendor advisories state broader impact.

Researcher notes

Evidence is limited to the CVE record, Linux stable commits, and Fedora package announcements. No CVSS, CWE, CPE mapping, exploit status, or complete affected-version semantics are provided in the bundle. Avoid overclaiming impact beyond NULL dereference and potential denial of service.

Mitigation direction

  • Update to a vendor kernel containing the Linux stable fix for CVE-2024-26998.
  • Review Fedora or other distribution advisories for backported package updates.
  • Prioritize hosts using serial devices, embedded hardware, or runtime power management.
  • If updates are delayed, monitor vendor guidance for supported operational workarounds.

Validation and detection

  • Inventory running Linux kernel versions across affected server, workstation, and embedded fleets.
  • Check distribution changelogs for CVE-2024-26998 or the referenced stable commits.
  • Confirm whether systems use 8250 or other serial drivers with runtime PM enabled.
  • Review kernel logs for NULL dereferences involving serial8250_tx_chars or pm_runtime_work.
Prepared
Confidence
medium
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2024-26998 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
7Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux434beb66368d4fb4d3119c2116b9398500adbf47, 43066e32227ecde674e8ae1fcdd4a1ede67680c2, 43066e32227ecde674e8ae1fcdd4a1ede67680c2, a629a9b2f7699314a4abe8fbc37b0ee667b60f33, 6.6.24, 6.7.12unaffected
LinuxLinux6.8, 0, 6.6.29, 6.8.8, 6.9affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.