CVE-2026-46130
Vulnérabilité non évaluée dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: dm-verity-fec: fix reading parity bytes split across blocks (take 3) fec_decode_bufs() assumes that the parity bytes of the first RS codeword it decodes are never split across parity blocks. This assumption is false. Consider v->fec->block_size == 4096 && v->fec->roots == 17 && fio->nbufs == 1, for example. In that case, each call to fec_decode_bufs() consumes v->fec->roots * (fio->nbufs << DM_VERITY_FEC_BUF_RS_BITS) = 272 parity bytes. Considering that the parity data for each message block starts on a block boundary, the byte alignment in the parity data will iterate through 272*i mod 4096 until the 3 parity blocks have been consumed. On the 16th call (i=15), the alignment will be 4080 bytes into the first block. Only 16 bytes remain in that block, but 17 parity bytes will be needed. The code reads out-of-bounds from the parity block buffer. Fortunately this doesn't normally happen, since it can occur only for certain non-default values of fec_roots *and* when the maximum number of buffers couldn't be allocated due to low memory. For example with block_size=4096 only the following cases are affected: fec_roots=17: nbufs in [1, 3, 5, 15] fec_roots=19: nbufs in [1, 229] fec_roots=21: nbufs in [1, 3, 5, 13, 15, 39, 65, 195] fec_roots=23: nbufs in [1, 89] Regardless, fix it by refactoring how the parity blocks are read.
Gravité et risque d'exploitation
CVE-2026-46130 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.16 %, ce qui la place devant 5.3 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions 6.13, <=7.0.*, 7.0.7, <3d1b4e2d8ac0a1a1390a117f61ce0ca1c47e3bcb, <6.13, 0, <d47281b9a4472cfd73122393e79fbe76b651e46a, 6.6.72, 6.18.42, 6bc6ee31113b05db605694491bdeb2b1730142f1, 7.1, <=6.18.*, <6.2, <6.7, <430a05cb926f6bdf53e81460a2c3a553257f3f61, <=*, 6.12.10, fc8943886629e26de34867db302c74d465510826, 12caa73a28f0ae147ec0356b45091edf2462462b, 6.1.125, 6df90c02bae468a3a6110bafbc659884d0c4966c) 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.