---
cve: "CVE-2026-90011"
severity: "CRITICAL"
cvss: 9.1
epss: "0.8%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-09-16 11:17:13"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T11:00:44+02:00"
---

# CVE-2026-90011

> 9.1 CRITICAL

## Beschreibung

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

scsi: target: iscsi: Reserve a terminator byte for the login payload

iscsi_target_check_login_request() rejects a login PDU whose
DataSegmentLength exceeds MAX_KEY_VALUE_PAIRS, but the test is '>' and
login->req_buf is allocated with exactly MAX_KEY_VALUE_PAIRS
bytes. Since iscsit_get_login_rx() receives payload_length + padding
bytes, where

	padding = ((-payload_length) & 3);

any payload_length from 8189 to 8192 fills the whole 8192 byte
buffer. The write stays in bounds, but no byte is left for a NUL
terminator.

The buffer is subsequently consumed as a C string. In the CHAP path
chap_check_algorithm() calls kstrdup(a_str), and extract_param() calls
strstr(in_buf, pattern) followed by strlen_semi(), none of which take a
length. convert_null_to_semi() additionally rewrites every embedded NUL
to ';', so even a payload made of well formed NUL separated key=value
records is left without a terminator. These walk past the end of the
object into adjacent slab memory. It is reachable by an unauthenticated
initiator against a portal configured for CHAP; when authentication is
not required iscsi_login_zero_tsih_s2() rewrites AuthMethod to None and
the CHAP path is never entered.

Allocate one extra byte. kzalloc() zeroes it and nothing ever writes to
it, as every writer copies to offset 0 for at most MAX_KEY_VALUE_PAIRS
bytes, so the buffer is always terminated.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- Kernel ≥ 5.10.270
- Kernel ≥ 5.15.221
- Kernel ≥ 6.1.188
- Kernel ≥ 6.6.157
- Kernel ≥ 6.12.110
- Kernel ≥ 6.18.51
- Kernel ≥ 7.2.5

## Referenzen

- <https://git.kernel.org/stable/c/5fac79f248c37774d1dd761406f83d25ca6ff8e4>
- <https://git.kernel.org/stable/c/6ddddcad436d8e6e619204d3c848147ff2f5bf1e>
- <https://git.kernel.org/stable/c/b19dc17ed963ac36c0db4b52a1803fb11169f91f>
- <https://git.kernel.org/stable/c/6b589ef9d5f6cdc70d2b4f269ca6cf26b5ebb076>
- <https://git.kernel.org/stable/c/eb9dadf4d552ebe10644871c5189286552aa48f5>
- <https://git.kernel.org/stable/c/1624bff4c5118ad494d50ad94d44f22064667a7f>
- <https://git.kernel.org/stable/c/3ddf3ea291a0ef2ea93b82e158960ac2cc42302b>
- <https://git.kernel.org/stable/c/f4825922d2fb371e2b969697d792077f1b62b62c>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-90011) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_