Answer in brief
CVE-2025-39673 records a Critical severity (CVSS 9.8) vulnerability in ppp: fix race conditions in ppp_fill_forward_path. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC CN 4100 (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC CN 4100 (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=f6efc675c9dd8d93f826b79ae7e33e03301db609 <9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7 || >=f6efc675c9dd8d93f826b79ae7e33e03301db609 <0f1630be6fcca3f0c63e4b242ad202e5cde28a40 || >=f6efc675c9dd8d93f826b79ae7e33e03301db609 <ca18d751bcc9faf5b7e82e9fae1223d103928181 || >=f6efc675c9dd8d93f826b79ae7e33e03301db609 <94731cc551e29511d85aa8dec61a6c071b1f2430 || >=f6efc675c9dd8d93f826b79ae7e33e03301db609 <f97f6475fdcb3c28ff3c55cc4b7bde632119ec08 || >=f6efc675c9dd8d93f826b79ae7e33e03301db609 <0417adf367a0af11adf7ace849af4638cfb573f7 | 9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7, 0f1630be6fcca3f0c63e4b242ad202e5cde28a40, ca18d751bcc9faf5b7e82e9fae1223d103928181, 94731cc551e29511d85aa8dec61a6c071b1f2430, f97f6475fdcb3c28ff3c55cc4b7bde632119ec08, 0417adf367a0af11adf7ace849af4638cfb573f7 |
| Linux/Linuxgeneric | 5.13 | Not reported |
| Siemens/SIMATIC CN 4100generic | >=0 <V5.0 | V5.0 |
Published upstream
Sep 5, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.