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NVD / CVE Program· CNA Linux

CVE-2025-39715: parisc: Revise gateway LWS calls to probe user read access

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: 0.15% (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 8bccf47adbf658293528e86960e6d6f736b1c9f7, 9b6af875baba9c4679b55f4561e201485451305f, bc0a24c24ceebabb5ba65900e332233d79e625e6; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1.

Low priority for now. Upgrade to Linux Linux 8bccf47adbf658293528e86960e6d6f736b1c9f7, 9b6af875baba9c4679b55f4561e201485451305f, bc0a24c24ceebabb5ba65900e332233d79e625e6; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1 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: parisc: Revise gateway LWS calls to probe user read access We use load and stbys,e instructions to trigger memory reference interruptions without writing to memory. Because of the way read access support is implemented, read access interruptions are only triggered at privilege levels 2 and 3. The kernel and gateway page execute at privilege level 0, so this code never triggers a read access interruption. Thus, it is currently possible for user code to execute a LWS compare and swap operation at an address that is read protected at privilege level 3 (PRIV_USER). Fix this by probing read access rights at privilege level 3 and branching to lws_fault if access isn't allowed.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Sep 5, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 4th percentile
CWE
—

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 · 0.1%

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.

Follow CVE-2025-39715

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 kernel5.17 and later · before 6.1.149
  • linux linux kernel6.2 and later · before 6.6.103
  • linux linux kernel6.7 and later · before 6.12.44
  • linux linux kernel6.13 and later · before 6.16.4

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

    • 5.17affected
    • d0585d742ff2d82accd26c661c60a6d260429c4a and later · before e8b496c52aa0c6572d88db7cab85aeea6f9c194daffected · git
    • d0585d742ff2d82accd26c661c60a6d260429c4a and later · before 8bccf47adbf658293528e86960e6d6f736b1c9f7affected · git
    • d0585d742ff2d82accd26c661c60a6d260429c4a and later · before bc0a24c24ceebabb5ba65900e332233d79e625e6affected · git
    • d0585d742ff2d82accd26c661c60a6d260429c4a and later · before 9b6af875baba9c4679b55f4561e201485451305faffected · git
    • d0585d742ff2d82accd26c661c60a6d260429c4a and later · before f6334f4ae9a4e962ba74b026e1d965dfdf8cbef8affected · git
    • before 5.17not affected · semver
    • 6.1.149 and later · up to and including 6.1.*not affected · semver
    • 6.6.103 and later · up to and including 6.6.*not affected · semver
    • 6.12.44 and later · up to and including 6.12.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.153-16.1.153-1
Debian:13linuxbefore 6.12.48-16.12.48-1
Debian:14linuxbefore 6.16.5-16.16.5-1

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-2025-39713Sep 5, 2025 · media: rainshadow-cec: fix TOCTOU race condition in rain_interrupt()
    18Monitor
  • ← EarlierCVE-2025-39714Sep 5, 2025 · media: usbtv: Lock resolution while streaming
    22Monitor
  • Later →CVE-2025-39716Sep 5, 2025 · parisc: Revise __get_user() to probe user read access
    22Monitor

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 Linux8bccf47adbf658293528e86960e6d6f736b1c9f7Vendor (CNA)
Linux Linux9b6af875baba9c4679b55f4561e201485451305fVendor (CNA)
Linux Linuxbc0a24c24ceebabb5ba65900e332233d79e625e6Vendor (CNA)
Linux Linuxe8b496c52aa0c6572d88db7cab85aeea6f9c194dVendor (CNA)
Linux Linuxf6334f4ae9a4e962ba74b026e1d965dfdf8cbef8Vendor (CNA)
azl3 kernel 6.6.96.2-2 on Azure Linux 3.06.6.104.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.153-1 · 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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)

—

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. Fix✗ → ✓

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

References

Show all references (6 more)

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

All records