EUVD-2026-39323
GHSA-grrc-m4h5-r55j
Severity by source
AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Trigger is a local probe-failure race plus an SFP hardware event (AV:L, AC:H, PR:L); realistic impact is a kernel crash/DoS, so A:H with no confirmed confidentiality or integrity impact.
Primary rating from Vendor (416baaa9-dc9f-4396-8d5f-8c081fb06d67).
CVSS VectorVendor: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
5DescriptionCVE.org
In the Linux kernel, the following vulnerability has been resolved:
net: phy: clean the sfp upstream if phy probing fails
Sashiko reported that we don't call sfp_bus_del_upstream() in the probe failure path, so let's add it, otherwise the sfp-bus is left with a dangling 'upstream' field, that may be used later on during SFP events.
This issue existed before the generic phylib sfp support, back when drivers were calling phy_sfp_probe themselves.
AnalysisAI
Use of a dangling pointer in the Linux kernel's phylib/SFP networking subsystem occurs when PHY probing fails but sfp_bus_del_upstream() is never called, leaving the sfp-bus 'upstream' field pointing at freed/torn-down state that can be dereferenced during a later SFP hot-plug event. Affected systems are Linux hosts and appliances using PHY drivers with SFP cage support across kernels from 5.5 up to the fix in commit 48774e87. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires a system using a PHY driver with SFP cage support where phy_probe() fails (e.g., due to a problematic transceiver, driver, or device-tree/hardware configuration), AND a subsequent SFP event (module insert/remove or link change) that walks the stale 'upstream' reference. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | Signals here conflict and the published CVSS overstates real-world risk. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker (or faulty hardware) causes PHY probing to fail on a network interface with an SFP cage, leaving the sfp-bus with a dangling upstream pointer; the attacker then induces an SFP event by inserting, removing, or toggling a transceiver module, causing the kernel to dereference freed state and crash or potentially corrupt memory. No public exploit code is identified, and realistically this typically manifests as a kernel oops/DoS rather than reliable code execution. |
| Remediation | Patch available per vendor advisory: upstream fix is kernel commit 48774e87bbaa0056819d4b52301e4692e50e3252 (https://git.kernel.org/stable/c/48774e87bbaa0056819d4b52301e4692e50e3252), which adds the missing sfp_bus_del_upstream() call in the phy probe failure path; update to the stable release that incorporates this commit (no single tagged release number was provided in the input, so confirm the exact backported version against your distribution's kernel changelog). … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Identify inventory of Linux systems running kernel 5.5 through the current version with SFP cage support. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
Same technique Information Disclosure
View allShare
External POC / Exploit Code
Leaving vuln.today