CVE-2025-39673ppp: fix race conditions in ppp_fill_forward_path
- 9.8CriticalCVSS base score
- 0.32%Exploitation in 30 daysEPSS · top 75% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By Linux
- 5 months later
· 5 months later
Published
- 14 months later
· 14 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | Medium4.7 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.32% · top 75% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
- affected f6efc675c9dd8d93f826b79ae7e33e03301db609 – < 9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7
- affected f6efc675c9dd8d93f826b79ae7e33e03301db609 – < 0f1630be6fcca3f0c63e4b242ad202e5cde28a40
- affected f6efc675c9dd8d93f826b79ae7e33e03301db609 – < ca18d751bcc9faf5b7e82e9fae1223d103928181
- affected f6efc675c9dd8d93f826b79ae7e33e03301db609 – < 94731cc551e29511d85aa8dec61a6c071b1f2430
- affected f6efc675c9dd8d93f826b79ae7e33e03301db609 – < f97f6475fdcb3c28ff3c55cc4b7bde632119ec08
- affected f6efc675c9dd8d93f826b79ae7e33e03301db609 – < 0417adf367a0af11adf7ace849af4638cfb573f7
- affected 5.13
- unaffected < 5.13
- unaffected 5.15.190 – ≤ 5.15.*
- unaffected 6.1.149 – ≤ 6.1.*
- unaffected 6.6.103 – ≤ 6.6.*
- unaffected 6.12.44 – ≤ 6.12.*
- unaffected 6.16.4 – ≤ 6.16.*
- unaffected 6.17 – ≤ *
References
References8
- https://git.kernel.org/stable/c/9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7 (opens in a new tab)
- https://git.kernel.org/stable/c/0f1630be6fcca3f0c63e4b242ad202e5cde28a40 (opens in a new tab)
- https://git.kernel.org/stable/c/ca18d751bcc9faf5b7e82e9fae1223d103928181 (opens in a new tab)
- https://git.kernel.org/stable/c/94731cc551e29511d85aa8dec61a6c071b1f2430 (opens in a new tab)
- https://git.kernel.org/stable/c/f97f6475fdcb3c28ff3c55cc4b7bde632119ec08 (opens in a new tab)
- https://git.kernel.org/stable/c/0417adf367a0af11adf7ace849af4638cfb573f7 (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html (opens in a new tab)
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-31551 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-39673)Record last updated .