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CVE-2021-47482

Vulnérabilité moyenne dans Linux (Linux)

CVSS 5.3 · Moyenne
EPSS 0.7%
Linux•Linux•Versions : <0c6b199f09be489c48622537a550787fc80aea73, 0, <07533f1a673ce1126d0a72ef1e4b5eaaa3dd6d20, <2.6.38, 4.9.289, c6c8fea29769d998d94fcec9b9f14d4b52b349d3, 5.4.157, <=4.9.*, <=5.10.*, <=4.14.*, 2.6.38, <6f68cd634856f8ca93bafd623ba5357e0f648c68, 5.10.77, <=5.4.*, 5.15, <=4.19.*, 4.19.215, <=4.4.*, 4.14.254, <=*, 5.14.16, <e50f957652190b5a88a8ebce7e5ab14ebd0d3f00, <fbf150b16a3635634b7dfb7f229d8fcd643c6c51, 4.4.293, <6422e8471890273994fe8cc6d452b0dcd2c9483e, <a8f7359259dd5923adc6129284fdad12fc5db347, <=5.14.*, <b0a2cd38553c77928ef1646ed1518486b1e70ae8

Description

In the Linux kernel, the following vulnerability has been resolved: net: batman-adv: fix error handling Syzbot reported ODEBUG warning in batadv_nc_mesh_free(). The problem was in wrong error handling in batadv_mesh_init(). Before this patch batadv_mesh_init() was calling batadv_mesh_free() in case of any batadv_*_init() calls failure. This approach may work well, when there is some kind of indicator, which can tell which parts of batadv are initialized; but there isn't any. All written above lead to cleaning up uninitialized fields. Even if we hide ODEBUG warning by initializing bat_priv->nc.work, syzbot was able to hit GPF in batadv_nc_purge_paths(), because hash pointer in still NULL. [1] To fix these bugs we can unwind batadv_*_init() calls one by one. It is good approach for 2 reasons: 1) It fixes bugs on error handling path 2) It improves the performance, since we won't call unneeded batadv_*_free() functions. So, this patch makes all batadv_*_init() clean up all allocated memory before returning with an error to no call correspoing batadv_*_free() and open-codes batadv_mesh_free() with proper order to avoid touching uninitialized fields.

Gravité et risque d'exploitation

CVE-2021-47482 obtient un score CVSS de 5.3/10, soit une gravité moyenne. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.74 %, ce qui la place devant 53.7 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <0c6b199f09be489c48622537a550787fc80aea73, 0, <07533f1a673ce1126d0a72ef1e4b5eaaa3dd6d20, <2.6.38, 4.9.289, c6c8fea29769d998d94fcec9b9f14d4b52b349d3, 5.4.157, <=4.9.*, <=5.10.*, <=4.14.*, 2.6.38, <6f68cd634856f8ca93bafd623ba5357e0f648c68, 5.10.77, <=5.4.*, 5.15, <=4.19.*, 4.19.215, <=4.4.*, 4.14.254, <=*, 5.14.16, <e50f957652190b5a88a8ebce7e5ab14ebd0d3f00, <fbf150b16a3635634b7dfb7f229d8fcd643c6c51, 4.4.293, <6422e8471890273994fe8cc6d452b0dcd2c9483e, <a8f7359259dd5923adc6129284fdad12fc5db347, <=5.14.*, <b0a2cd38553c77928ef1646ed1518486b1e70ae8) 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.

Références

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