CVE-2025-38433
Vulnérabilité non évaluée dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: riscv: fix runtime constant support for nommu kernels the `__runtime_fixup_32` function does not handle the case where `val` is zero correctly (as might occur when patching a nommu kernel and referring to a physical address below the 4GiB boundary whose upper 32 bits are all zero) because nothing in the existing logic prevents the code from taking the `else` branch of both nop-checks and emitting two `nop` instructions. This leaves random garbage in the register that is supposed to receive the upper 32 bits of the pointer instead of zero that when combined with the value for the lower 32 bits yields an invalid pointer and causes a kernel panic when that pointer is eventually accessed. The author clearly considered the fact that if the `lui` is converted into a `nop` that the second instruction needs to be adjusted to become an `li` instead of an `addi`, hence introducing the `addi_insn_mask` variable, but didn't follow that logic through fully to the case where the `else` branch executes. To fix it just adjust the logic to ensure that the second `else` branch is not taken if the first instruction will be patched to a `nop`.
Gravité et risque d'exploitation
CVE-2025-38433 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 0.15 %, ce qui la place devant 3.7 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions <=6.15.*, <=*, <0a24b00dcde83934a3cc13e4c6b775522903496b, 6.16, <8d90d9872edae7e78c3a12b98e239bfaa66f3639, <6.15, 0, a44fb5722199de8338d991db5ad3d509192179bb, 6.15, 6.15.5) 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.