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NVD / CVE Program· CNA Linux

CVE-2025-38100: x86/iopl: Cure TIF_IO_BITMAP inconsistencies

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.21% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 2cfcbe1554c119402e7382de974c26b0549899fe, 2dace5e016c991424a3dc6e83b1ae5dca8992d08, 73cfcc8445585b8af7e18be3c9246b851fdf336c; azl3 kernel 6.6.92.2-2 on Azure Linux 3.0 6.6.96.1-1; azl3 kernel 6.6.96.1-1 on Azure Linux 3.0 6.6.96.1-1.

Low priority for now. Upgrade to Linux Linux 2cfcbe1554c119402e7382de974c26b0549899fe, 2dace5e016c991424a3dc6e83b1ae5dca8992d08, 73cfcc8445585b8af7e18be3c9246b851fdf336c; azl3 kernel 6.6.92.2-2 on Azure Linux 3.0 6.6.96.1-1; azl3 kernel 6.6.96.1-1 on Azure Linux 3.0 6.6.96.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: x86/iopl: Cure TIF_IO_BITMAP inconsistencies io_bitmap_exit() is invoked from exit_thread() when a task exists or when a fork fails. In the latter case the exit_thread() cleans up resources which were allocated during fork(). io_bitmap_exit() invokes task_update_io_bitmap(), which in turn ends up in tss_update_io_bitmap(). tss_update_io_bitmap() operates on the current task. If current has TIF_IO_BITMAP set, but no bitmap installed, tss_update_io_bitmap() crashes with a NULL pointer dereference. There are two issues, which lead to that problem: 1) io_bitmap_exit() should not invoke task_update_io_bitmap() when the task, which is cleaned up, is not the current task. That's a clear indicator for a cleanup after a failed fork(). 2) A task should not have TIF_IO_BITMAP set and neither a bitmap installed nor IOPL emulation level 3 activated. This happens when a kernel thread is created in the context of a user space thread, which has TIF_IO_BITMAP set as the thread flags are copied and the IO bitmap pointer is cleared. Other than in the failed fork() case this has no impact because kernel threads including IO workers never return to user space and therefore never invoke tss_update_io_bitmap(). Cure this by adding the missing cleanups and checks: 1) Prevent io_bitmap_exit() to invoke task_update_io_bitmap() if the to be cleaned up task is not the current task. 2) Clear TIF_IO_BITMAP in copy_thread() unconditionally. For user space forks it is set later, when the IO bitmap is inherited in io_bitmap_share(). For paranoia sake, add a warning into tss_update_io_bitmap() to catch the case, when that code is invoked with inconsistent state.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jul 3, 2025
Updated
Nov 5, 2026
EPSS
0.2% · 11th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux11.0
  • linux linux kernel5.11 and later · before 5.15.186
  • linux linux kernel5.16 and later · before 6.1.142
  • linux linux kernel5.5 and later · before 5.10.239
  • linux linux kernel6.7 and later · before 6.12.34
  • linux linux kernel6.13 and later · before 6.15.3
  • linux linux kernel6.2 and later · before 6.6.94

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.5affected
    • ea5f1cd7ab494f65f50f338299eabb40ad6a1767 and later · before d64b7b05a827f98d068f412969eef65489b0cf03affected · git
    • ea5f1cd7ab494f65f50f338299eabb40ad6a1767 and later · before 2dace5e016c991424a3dc6e83b1ae5dca8992d08affected · git
    • ea5f1cd7ab494f65f50f338299eabb40ad6a1767 and later · before aa5ce1485562f20235b4c759eee5ab0c41d2c220affected · git
    • ea5f1cd7ab494f65f50f338299eabb40ad6a1767 and later · before 2cfcbe1554c119402e7382de974c26b0549899feaffected · git
    • ea5f1cd7ab494f65f50f338299eabb40ad6a1767 and later · before b3b3b6366dc8eb5b22edba9adc4bff3cdacfd64caffected · git
    • ea5f1cd7ab494f65f50f338299eabb40ad6a1767 and later · before 73cfcc8445585b8af7e18be3c9246b851fdf336caffected · git
    • ea5f1cd7ab494f65f50f338299eabb40ad6a1767 and later · before 8b68e978718f14fdcb080c2a7791c52a0d09bc6daffected · git
    • before 5.5not affected · semver
    • 5.10.239 and later · up to and including 5.10.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.147-16.1.147-1
Debian:13linuxbefore 6.12.35-16.12.35-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-38097Jul 3, 2025 · espintcp: remove encap socket caching to avoid reference leak
    22Monitor
  • ← EarlierCVE-2025-38099Jul 3, 2025 · Bluetooth: Disable SCO support if READ_VOICE_SETTING is unsupported/broken
    22Monitor
  • Later →CVE-2025-38102Jul 3, 2025 · VMCI: fix race between vmci_host_setup_notify and vmci_ctx_unset_notify
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux2cfcbe1554c119402e7382de974c26b0549899feVendor (CNA)
Linux Linux2dace5e016c991424a3dc6e83b1ae5dca8992d08Vendor (CNA)
Linux Linux73cfcc8445585b8af7e18be3c9246b851fdf336cVendor (CNA)
Linux Linux8b68e978718f14fdcb080c2a7791c52a0d09bc6dVendor (CNA)
Linux Linuxaa5ce1485562f20235b4c759eee5ab0c41d2c220Vendor (CNA)
Linux Linuxb3b3b6366dc8eb5b22edba9adc4bff3cdacfd64cVendor (CNA)
Linux Linuxd64b7b05a827f98d068f412969eef65489b0cf03Vendor (CNA)
azl3 kernel 6.6.92.2-2 on Azure Linux 3.06.6.96.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kernel 6.6.96.1-1 on Azure Linux 3.06.6.96.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.147-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (9 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records