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.
CVE-2025-39673
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2025-39673
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
"lessThan": "9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7",
"versionType": "git"
},
{
"status": "affected",
"version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
"lessThan": "0f1630be6fcca3f0c63e4b242ad202e5cde28a40",
"versionType": "git"
},
{
"status": "affected",
"version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
"lessThan": "ca18d751bcc9faf5b7e82e9fae1223d103928181",
"versionType": "git"
},
{
"status": "affected",
"version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
"lessThan": "94731cc551e29511d85aa8dec61a6c071b1f2430",
"versionType": "git"
},
{
"status": "affected",
"version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
"lessThan": "f97f6475fdcb3c28ff3c55cc4b7bde632119ec08",
"versionType": "git"
},
{
"status": "affected",
"version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
"lessThan": "0417adf367a0af11adf7ace849af4638cfb573f7",
"versionType": "git"
}
],
"programFiles": [
"drivers/net/ppp/ppp_generic.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.13"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.13",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.15.190",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.149",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.103",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.44",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.16.4",
"versionType": "semver",
"lessThanOrEqual": "6.16.*"
},
{
"status": "unaffected",
"version": "6.17",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/net/ppp/ppp_generic.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2025-39673
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #30616 · Revision 1
- Added to Heist Feed
- Publisher date