CVE-2025-39673ppp: fix race conditions in ppp_fill_forward_path
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 15, 2026
Affected products
Linux Linux linux:linux (from the name) | from f6efc675c9dd8d93f826b79ae7e33e03301db609 before 9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7; from f6efc675c9dd8d93f826b79ae7e33e03301db609 before 0f1630be6fcca3f0c63e4b242ad202e5cde28a40; from f6efc675c9dd8d93f826b79ae7e33e03301db609 before ca18d751bcc9faf5b7e82e9fae1223d103928181; from f6efc675c9dd8d93f826b79ae7e33e03301db609 before 94731cc551e29511d85aa8dec61a6c071b1f2430; from f6efc675c9dd8d93f826b79ae7e33e03301db609 before f97f6475fdcb3c28ff3c55cc4b7bde632119ec08; from f6efc675c9dd8d93f826b79ae7e33e03301db609 before 0417adf367a0af11adf7ace849af4638cfb573f7 | CNA record |
Siemens SIMATIC CN 4100 siemens:simatic_cn_4100 (from the name) | before V5.0 | CISA ADP |
linux linux_kernel linux:linux_kernel | from 5.13 before 5.15.190; from 5.16 before 6.1.149; from 6.2 before 6.6.103; from 6.7 before 6.12.44; from 6.13 before 6.16.4; 6.17; 6.17 | NVD |
debian debian_linux debian:debian_linux | 11.0 | NVD |
References
- https://git.kernel.org/stable/c/9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7patch
- https://git.kernel.org/stable/c/0f1630be6fcca3f0c63e4b242ad202e5cde28a40patch
- https://git.kernel.org/stable/c/ca18d751bcc9faf5b7e82e9fae1223d103928181patch
- https://git.kernel.org/stable/c/94731cc551e29511d85aa8dec61a6c071b1f2430patch
- https://git.kernel.org/stable/c/f97f6475fdcb3c28ff3c55cc4b7bde632119ec08patch
- https://git.kernel.org/stable/c/0417adf367a0af11adf7ace849af4638cfb573f7patch
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlthird-party-advisory
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.