CVE-2025-39790
What it is
In the Linux kernel, the following vulnerability has been resolved: bus: mhi: host: Detect events pointing to unexpected TREs When a remote device sends a completion event to the host, it contains a pointer to the consumed TRE. The host uses this pointer to process all of the TREs between it and the host's local copy of the ring's read pointer. This works when processing completion for chained transactions, but can lead to nasty results if the device sends an event for a single-element transaction with a read pointer that is multiple elements ahead of the host's read pointer. For instance, if the host accesses an event ring while the device is updating it, the pointer inside of the event might still point to an old TRE. If the host uses the channel's xfer_cb() to directly free the buffer pointed to by the TRE, the buffer will be double-freed. This behavior was observed on an ep that used upstream EP stack without 'commit 6f18d174b73d ("bus: mhi: ep: Update read pointer only after buffer is written")'. Where the device updated the events ring pointer before updating the event contents, so it left a window where the host was able to access the stale data the event pointed to, before the device had the chance to update them. The usual pattern was that the host received an event pointing to a TRE that is not immediately after the last processed one, so it got treated as if it was a chained transaction, processing all of the TREs in between the two read pointers. This commit aims to harden the host by ensuring transactions where the event points to a TRE that isn't local_rp + 1 are chained. [mani: added stable tag and reworded commit message]
At a glance
- Exploitability
- Can be exploited locally on the machine without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 8.4 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Weakness
- CWE-415
- Record status
- Modified
Affected
- Linux Kernel < 5.15.190
- Linux Kernel < 6.1.149
- Linux Kernel < 6.6.103
- Linux Kernel < 6.12.44
- Linux Kernel < 6.16.4
- Debian Linux 11.0
Attack profile CVSS 3.1 · 8.4
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2025-39790.md and follow it. Check whether this project is affected by CVE-2025-39790. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/2ec99b922f4661521927eeada76f431eebfbabc4
- https://git.kernel.org/stable/c/4079c6c59705b96285219b9efc63cab870d757b7
- https://git.kernel.org/stable/c/44e1a079e18f78d6594a715b0c6d7e18c656f7b9
- https://git.kernel.org/stable/c/5bd398e20f0833ae8a1267d4f343591a2dd20185
- https://git.kernel.org/stable/c/5e17429679a8545afe438ce7a82a13a54e8ceabb
- https://git.kernel.org/stable/c/7b3f0e3b60c27f4fcb69927d84987e5fd6240530
References
- https://git.kernel.org/stable/c/2ec99b922f4661521927eeada76f431eebfbabc4
- https://git.kernel.org/stable/c/4079c6c59705b96285219b9efc63cab870d757b7
- https://git.kernel.org/stable/c/44e1a079e18f78d6594a715b0c6d7e18c656f7b9
- https://git.kernel.org/stable/c/5bd398e20f0833ae8a1267d4f343591a2dd20185
- https://git.kernel.org/stable/c/5e17429679a8545afe438ce7a82a13a54e8ceabb
- https://git.kernel.org/stable/c/7b3f0e3b60c27f4fcb69927d84987e5fd6240530
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html