---
cve: "CVE-2026-68462"
severity: "HIGH"
cvss: 7.8
epss: "12%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-08-15 06:18:39"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-03T06:25:28+02:00"
---

# CVE-2026-68462

> 7.8 HIGH

## Beschreibung

In the Linux kernel, the following vulnerability has been resolved:

bpf: Reject negative const offsets for buffer pointers

The verifier rejects variable offsets for PTR_TO_TP_BUFFER and PTR_TO_BUF
accesses, but it currently accepts a constant negative offset produced by
pointer arithmetic.

Commit 022ac0750883 ("bpf: use reg->var_off instead of reg->off for
pointers") moved constant pointer offsets from reg->off to reg->var_off.
However, __check_buffer_access() continued to check only the instruction
offset. An access with reg->var_off equal to -8 and an instruction offset
of zero therefore passes verification.

For writable raw tracepoints, the access end is also calculated from the
unsigned reg->var_off.value. An eight-byte access starting at -8 wraps
the calculated end to zero, allowing the program to load and attach
without increasing max_tp_access.

After ensuring that reg->var_off is constant, calculate the effective
access start using signed arithmetic and reject it when it is negative.
Use the validated start to calculate the access end for both
PTR_TO_TP_BUFFER and PTR_TO_BUF.

## CVSS-Vektor

```
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- Kernel ≥ 7.1.5

## Referenzen

- <https://git.kernel.org/stable/c/314bd592085c0720ef519f6edbc5f41440ff78d4>
- <https://git.kernel.org/stable/c/fd4cfa8c8f9a17cdec0539334d28754bc1d8a5d9>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-68462) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_