{"id":"CVE-2025-39673","url":"https://www.cyber-defence.io/tools/cve/CVE-2025-39673","generatedAt":"2026-10-27T23:58:04.239Z","title":"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.","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nppp: fix race conditions in ppp_fill_forward_path\n\nppp_fill_forward_path() has two race conditions:\n\n1. The ppp->channels list can change between list_empty() and\n   list_first_entry(), as ppp_lock() is not held. If the only channel\n   is deleted in ppp_disconnect_channel(), list_first_entry() may\n   access an empty head or a freed entry, and trigger a panic.\n\n2. pch->chan can be NULL. When ppp_unregister_channel() is called,\n   pch->chan is set to NULL before pch is removed from ppp->channels.\n\nFix these by using a lockless RCU approach:\n- Use list_first_or_null_rcu() to safely test and access the first list\n  entry.\n- Convert list modifications on ppp->channels to their RCU variants and\n  add synchronize_net() after removal.\n- Check for a NULL pch->chan before dereferencing it.","published":"2025-09-05T18:15:43.000Z","lastModified":"2026-10-19T21:10:00.000Z","status":"Modified","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":4.7,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-362"],"affected":["linux/linux kernel","debian/debian linux"],"epss":{"score":0.00308,"percentile":0.23432,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.31%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/0417adf367a0af11adf7ace849af4638cfb573f7","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/0f1630be6fcca3f0c63e4b242ad202e5cde28a40","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/94731cc551e29511d85aa8dec61a6c071b1f2430","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ca18d751bcc9faf5b7e82e9fae1223d103928181","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f97f6475fdcb3c28ff3c55cc4b7bde632119ec08","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-032379.html","source":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-39673","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}