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CVE Record

CVE-2025-39763: ACPI: APEI: send SIGBUS to current task if synchronous memory error not recovered

In the Linux kernel, the following vulnerability has been resolved: ACPI: APEI: send SIGBUS to current task if synchronous memory error not recovered If a synchronous error is detected as a result of user-space process triggering a 2-bit uncorrected error, the CPU will take a synchronous error exception such as Synchronous External Abort (SEA) on Arm64. The kernel will queue a memory_failure() work which poisons the related page, unmaps the page, and then sends a SIGBUS to the process, so that a system wide panic can be avoided. However, no memory_failure() work will be queued when abnormal synchronous errors occur. These errors can include situations like invalid PA, unexpected severity, no memory failure config support, invalid GUID section, etc. In such a case, the user-space process will trigger SEA again. This loop can potentially exceed the platform firmware threshold or even trigger a kernel hard lockup, leading to a system reboot. Fix it by performing a force kill if no memory_failure() work is queued for synchronous errors. [ rjw: Changelog edits ]

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

A Linux kernel error-handling flaw can let a user-space process repeatedly trigger unrecovered synchronous memory errors instead of being killed. On affected systems, that loop may exceed firmware thresholds or cause a kernel hard lockup, leading to reboot. The sources do not provide CVSS, CWE, or evidence of active exploitation.

Executive priority

Treat as a moderate availability risk for affected Linux fleets. Prioritize systems where unexpected reboot creates service impact, but do not escalate as known-exploited based on the supplied sources.

Technical view

In ACPI APEI handling, abnormal synchronous errors may avoid queuing memory_failure() work. The faulting process can then trigger the same synchronous exception again, including Arm64 SEA cases. The fix force-kills the current task when no memory_failure() work is queued for synchronous errors.

Likely exposure

Exposure is likely limited to Linux systems running affected kernel versions or commits with ACPI APEI synchronous error handling, especially Arm64 platforms where SEA can occur. The supplied data lists Linux as affected but does not identify distributions, appliances, or cloud images.

Exploitation context

No KEV listing or supplied source reports active exploitation. The described impact is availability loss: a user-space process triggers abnormal synchronous errors, causing repeated exceptions that may end in hard lockup or reboot. The bundle does not describe remote exploitation.

Researcher notes

The evidence supports a local denial-of-service style kernel availability issue tied to abnormal synchronous memory error paths. Affected-version data is sparse and branch-oriented, so validation should rely on vendor backport status and commit presence.

Mitigation direction

  • Check your vendor kernel advisory for CVE-2025-39763 coverage.
  • Update to a kernel containing the referenced stable fixes.
  • Prioritize affected Arm64 systems using ACPI APEI error handling.
  • Track distribution backports instead of relying only on upstream version numbers.

Validation and detection

  • Inventory Linux kernel versions and vendor build identifiers.
  • Compare installed kernels against vendor CVE-2025-39763 advisories.
  • Confirm whether referenced stable commits are present or backported.
  • Review incident logs for repeated synchronous error exceptions or unexpected reboots.
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

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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
0ADP providers
7Source links

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.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux8fcc4ae6faf8b455eeef00bc9ae70744e3b0f462, 8fcc4ae6faf8b455eeef00bc9ae70744e3b0f462, 8fcc4ae6faf8b455eeef00bc9ae70744e3b0f462, 8fcc4ae6faf8b455eeef00bc9ae70744e3b0f462, 8fcc4ae6faf8b455eeef00bc9ae70744e3b0f462, 8fcc4ae6faf8b455eeef00bc9ae70744e3b0f462, af02933d59bd1621a48d8b0b331cca9e530ba14b, 5.4.69unaffected
LinuxLinux5.8, 0, 6.1.164, 6.6.103, 6.12.43, 6.15.11, 6.16.2, 6.17affected
Weakness

CWE details

No CWE listed

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