CVE-2025-39673

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Source
https://cve.org/CVERecord?id=CVE-2025-39673
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-39673.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2025-39673
Downstream
Related
Published
2025-09-05T17:20:38.769Z
Modified
2026-03-20T12:43:00.384131Z
Summary
ppp: fix race conditions in ppp_fill_forward_path
Details

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

ppp: fix race conditions in pppfillforward_path

pppfillforward_path() has two race conditions:

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

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

Fix these by using a lockless RCU approach: - Use listfirstornullrcu() 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.

Database specific 
{
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39673.json"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
f6efc675c9dd8d93f826b79ae7e33e03301db609
Fixed
9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7
Fixed
0f1630be6fcca3f0c63e4b242ad202e5cde28a40
Fixed
ca18d751bcc9faf5b7e82e9fae1223d103928181
Fixed
94731cc551e29511d85aa8dec61a6c071b1f2430
Fixed
f97f6475fdcb3c28ff3c55cc4b7bde632119ec08
Fixed
0417adf367a0af11adf7ace849af4638cfb573f7

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-39673.json"