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NVD / CVE Program· CNA Linux

CVE-2025-39784: PCI: Fix link speed calculation on retrain failure

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: 0.13% (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 16557320f378262b5c605b15edebd3642406992a, 9989e0ca7462c62f93dbc62f684448aa2efb9226.

Low priority for now. Upgrade to Linux Linux 16557320f378262b5c605b15edebd3642406992a, 9989e0ca7462c62f93dbc62f684448aa2efb9226 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: PCI: Fix link speed calculation on retrain failure When pcie_failed_link_retrain() fails to retrain, it tries to revert to the previous link speed. However it calculates that speed from the Link Control 2 register without masking out non-speed bits first. PCIE_LNKCTL2_TLS2SPEED() converts such incorrect values to PCI_SPEED_UNKNOWN (0xff), which in turn causes a WARN splat in pcie_set_target_speed(): pci 0000:00:01.1: [1022:14ed] type 01 class 0x060400 PCIe Root Port pci 0000:00:01.1: broken device, retraining non-functional downstream link at 2.5GT/s pci 0000:00:01.1: retraining failed WARNING: CPU: 1 PID: 1 at drivers/pci/pcie/bwctrl.c:168 pcie_set_target_speed RDX: 0000000000000001 RSI: 00000000000000ff RDI: ffff9acd82efa000 pcie_failed_link_retrain pci_device_add pci_scan_single_device Mask out the non-speed bits in PCIE_LNKCTL2_TLS2SPEED() and PCIE_LNKCAP_SLS2SPEED() so they don't incorrectly return PCI_SPEED_UNKNOWN. [bhelgaas: commit log, add details from https://lore.kernel.org/r/1c92ef6bcb314ee6977839b46b393282e4f52e74.1750684771.git.lukas@wunner.de]

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Sep 11, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 2th 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

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  • when exploit code appears or is weaponized
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  • 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

Affected versions

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

  • 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

    • 6.13affected
    • de9a6c8d5dbfedb5eb3722c822da0490f6a59a45 and later · before 16557320f378262b5c605b15edebd3642406992aaffected · git
    • de9a6c8d5dbfedb5eb3722c822da0490f6a59a45 and later · before 9989e0ca7462c62f93dbc62f684448aa2efb9226affected · git
    • before 6.13not affected · semver
    • 6.16.4 and later · up to and including 6.16.*not affected · semver
    • 6.17 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
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-2025-39782Sep 11, 2025 · jbd2: prevent softlockup in jbd2_log_do_checkpoint()
    22Monitor
  • ← EarlierCVE-2025-39783Sep 11, 2025 · PCI: endpoint: Fix configfs group list head handling
    31Monitor
  • Later →CVE-2025-39785Sep 11, 2025 · drm/hisilicon/hibmc: fix irq_request()'s irq name variable is local
    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 Linux16557320f378262b5c605b15edebd3642406992aVendor (CNA)
Linux Linux9989e0ca7462c62f93dbc62f684448aa2efb9226Vendor (CNA)
debian:linux6.16.5-1 · Debian:14Package 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 (1 more)

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

All records