4.7

CVE-2025-39673

ppp: fix race conditions in ppp_fill_forward_path

In the Linux kernel, the following vulnerability has been resolved:

ppp: fix race conditions in ppp_fill_forward_path

ppp_fill_forward_path() has two race conditions:

1. The ppp->channels list can change between list_empty() and
   list_first_entry(), as ppp_lock() is not held. If the only channel
   is deleted in ppp_disconnect_channel(), list_first_entry() may
   access an empty head or a freed entry, and trigger a panic.

2. pch->chan can be NULL. When ppp_unregister_channel() is called,
   pch->chan is set to NULL before pch is removed from ppp->channels.

Fix these by using a lockless RCU approach:
- Use list_first_or_null_rcu() to safely test and access the first list
  entry.
- Convert list modifications on ppp->channels to their RCU variants and
  add synchronize_net() after removal.
- Check for a NULL pch->chan before dereferencing it.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 5.13 < 5.15.190
Linux ≫ Linux Kernel Version >= 5.16 < 6.1.149
Linux ≫ Linux Kernel Version >= 6.2 < 6.6.103
Linux ≫ Linux Kernel Version >= 6.7 < 6.12.44
Linux ≫ Linux Kernel Version >= 6.13 < 6.16.4
Linux ≫ Linux Kernel Version6.17 Updaterc1
Linux ≫ Linux Kernel Version6.17 Updaterc2
Debian ≫ Debian Linux Version11.0
VulnDex Vulnerability Enrichment
Diese Information steht angemeldeten Benutzern zur Verfügung. Login Login
Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.11% 0.013
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 4.7 1 3.6
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

https://git.kernel.org/stable/c/9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7
Patch
https://git.kernel.org/stable/c/0f1630be6fcca3f0c63e4b242ad202e5cde28a40
Patch
https://git.kernel.org/stable/c/ca18d751bcc9faf5b7e82e9fae1223d103928181
Patch
https://git.kernel.org/stable/c/94731cc551e29511d85aa8dec61a6c071b1f2430
Patch
https://git.kernel.org/stable/c/f97f6475fdcb3c28ff3c55cc4b7bde632119ec08
Patch
https://git.kernel.org/stable/c/0417adf367a0af11adf7ace849af4638cfb573f7
Patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
Third Party Advisory
https://cert-portal.siemens.com/productcert/html/ssa-032379.html