CVE-2026-45859
Vulnérabilité élevée dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_queue: do shared-unconfirmed check before segmentation Ulrich reports a regression with nfqueue: If an application did not set the 'F_GSO' capability flag and a gso packet with an unconfirmed nf_conn entry is received all packets are now dropped instead of queued, because the check happens after skb_gso_segment(). In that case, we did have exclusive ownership of the skb and its associated conntrack entry. The elevated use count is due to skb_clone happening via skb_gso_segment(). Move the check so that its peformed vs. the aggregated packet. Then, annotate the individual segments except the first one so we can do a 2nd check at reinject time. For the normal case, where userspace does in-order reinjects, this avoids packet drops: first reinjected segment continues traversal and confirms entry, remaining segments observe the confirmed entry. While at it, simplify nf_ct_drop_unconfirmed(): We only care about unconfirmed entries with a refcnt > 1, there is no need to special-case dying entries. This only happens with UDP. With TCP, the only unconfirmed packet will be the TCP SYN, those aren't aggregated by GRO. Next patch adds a udpgro test case to cover this scenario.
Gravité et risque d'exploitation
CVE-2026-45859 obtient un score CVSS de 7.5/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.61 %, ce qui la place devant 48.3 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions <=6.12.*, 0, 7.0, 6.12.75, 7d8dc1c7be8d3509e8f5164dd5df64c8e34d7eeb, 6.6.48, 74e6eb7fd27ef1ccc68041dbc66e6d80d2e4a1a0, <=6.19.*, <79b713ef4261a8ead96af4703f89d0b5f25532e2, 6c4a0ba674f410ab99a30a16f32dac0ebfed5cd3, <23901aa6b8a2f294c4b774436b4691f3ff863a8f, <5.16, 6.1.107, <=6.18.*, <6.2, <6.7, <6.11, 6.19.4, 025b3326c5c409b372d0103ad30f174e55adbd1b, 6.11, <=*, 6dcc8ba8a6074bb79040f502dc66ad23a58a1c86, <207b3ebacb6113acaaec0d171d5307032c690004, <b740e7ddd7ca0dbfeafca3f5e52717206cf28524, 6.10.7, 5.15.166, 6.18.14) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.