CVE-2026-98044
Vulnérabilité non évaluée dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject legacy packet loads from callbacks check_ld_abs() models a failed BPF_LD_ABS or BPF_LD_IND in a subprogram as an implicit return with R0 set to zero. It calls prepare_func_exit() to explore this synthesized path. When the load is reached directly from a synchronous callback, prepare_func_exit() enforces the callback return contract and marks R0 precise. R0 is not derived from a real instruction on this path, so precision backtracking reaches the callback call with R0 still requested and triggers the "callback unexpected regs" verifier bug. A privileged program loader can therefore cause a verifier warning and an -EFAULT BPF_PROG_LOAD. These legacy packet-load instructions are deprecated. Reject them from callbacks rather than complicating their implicit-return model. Check all active frames before constructing the implicit return so nested static subprograms cannot hide the callback context. Global functions are verified independently with a fresh frame zero, so an active-frame check cannot identify a global function called from a callback. Also check the complete subprogram call graph during stack-depth validation and reject a function containing a legacy load when any caller is a callback. This covers global and static descendants without making has_ld_abs transitive, preserving its per-function BTF return-type check. Ordinary uses outside callbacks remain supported.
Gravité et risque d'exploitation
CVE-2026-98044 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 0.17 %, ce qui la place devant 5.5 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions <5.11, ce01a4e5cfac7adbe0be565f90cd32ecbb2f8337, 7.2.7, 6.12.101, 6.18.53, <6.13, 0, 928d354ae3557e8f755a227e67be88034eb3cd7f, 8a800497d9f6c2ec9c2c1ba7b71d0ac2ea7f7bbe, <7.1, 5.15.216, ee861486e377edc55361c08dcbceab3f6b6577bd, d846d83bdacbd8f14fc45c63b8c1d22608452e1c, <6.18.53, <3484a99303912db62428494a9061212049027e57, 6.18.42, 6.1.183, <5.16, 7.1, <=6.18.*, <bc489c0c9b8c86bd7fac42cfd1bb152f042fca56, 7.0.10, <6.2, <=7.2.*, <6.7, <e7d28823c662128caae63f14e16bd394916c139b, <=*, de1055e7f9e67af32b1f3376066272b04e5223c0, 8674e2db06cff6b50f2216eed9a761d15425bb34, 5.10.265, 6.6.148, 37ad2bb11e9de92cb7b94548705eeedd87f7d392, 7.3) 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.