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CVE Record

CVE-2025-39920: pcmcia: Add error handling for add_interval() in do_validate_mem()

In the Linux kernel, the following vulnerability has been resolved: pcmcia: Add error handling for add_interval() in do_validate_mem() In the do_validate_mem(), the call to add_interval() does not handle errors. If kmalloc() fails in add_interval(), it could result in a null pointer being inserted into the linked list, leading to illegal memory access when sub_interval() is called next. This patch adds an error handling for the add_interval(). If add_interval() returns an error, the function will return early with the error code.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2025-39920 is a Linux kernel defect in PCMCIA memory validation. If memory allocation fails, the kernel could place an invalid entry into an internal list, causing illegal memory access later. The public sources do not provide a CVSS score, confirmed impact scope, or exploitation evidence.

Executive priority

Treat this as a kernel maintenance item, not an emergency based on current evidence. Prioritize normal kernel patch cycles, with faster action for exposed legacy, embedded, or hardware-adjacent Linux systems where PCMCIA support may exist.

Technical view

The issue is in do_validate_mem() in the Linux kernel PCMCIA code. add_interval() could fail after kmalloc(), but the caller did not handle that error. A null pointer could then be inserted into a linked list and later accessed by sub_interval(). Stable kernel commits add early error return handling.

Likely exposure

Exposure is most relevant to Linux systems running affected kernel versions with PCMCIA support reachable. The bundle lists Linux as affected and includes kernel stable fixes plus Debian LTS advisories. Exact exposure depends on distribution backports, kernel configuration, and whether PCMCIA code is present or used.

Exploitation context

No active exploitation is stated in the provided sources, and the CVE is not marked KEV. The described trigger depends on allocation failure in a kernel PCMCIA code path. Public evidence is insufficient to claim remote exploitability, privilege escalation, or reliable exploitation.

Researcher notes

The root cause is missing error propagation from add_interval() in do_validate_mem(). The fix pattern is defensive: return early when add_interval() fails. Public data does not include CVSS, CWE, exploitability analysis, or a complete affected-version matrix beyond kernel and Debian references.

Mitigation direction

  • Apply vendor kernel updates that include the referenced stable fixes.
  • Review Debian LTS advisories if using Debian LTS kernels.
  • Check distribution advisories for backported fixed kernel packages.
  • Prioritize systems with PCMCIA support enabled or relevant hardware exposure.
  • If no package is available, follow vendor guidance for interim risk reduction.

Validation and detection

  • Inventory Linux kernel versions across servers, endpoints, and embedded systems.
  • Confirm whether PCMCIA support is built in, loaded, or unused.
  • Map installed kernels against vendor advisories and stable fix commits.
  • Verify patched systems boot into the updated kernel.
  • Track exceptions where vendor status or backport coverage is unclear.
Prepared
Confidence
medium
Sources
12

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-2025-39920 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
1ADP providers
11Source 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.

ADP provider summaries

CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux7b4884ca8853a638df0eb5d251d80d67777b8b1a, 7b4884ca8853a638df0eb5d251d80d67777b8b1a, 7b4884ca8853a638df0eb5d251d80d67777b8b1a, 7b4884ca8853a638df0eb5d251d80d67777b8b1a, 7b4884ca8853a638df0eb5d251d80d67777b8b1a, 7b4884ca8853a638df0eb5d251d80d67777b8b1a, 7b4884ca8853a638df0eb5d251d80d67777b8b1a, 7b4884ca8853a638df0eb5d251d80d67777b8b1aunaffected
LinuxLinux2.6.34, 0, 5.4.299, 5.10.243, 5.15.192, 6.1.151, 6.6.105, 6.12.46, 6.16.6, 6.17affected
Weakness

CWE details

No CWE listed

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