Critical

CVE-2026-90011 — scsi: target: iscsi: Reserve a terminator byte for the login payload

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.

Published Sep 16, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (critical)+10

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Linux

CVSS base

9.1

Critical · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ e48354ce078c079996f89d715dfa44814b4eba01 and < 5fac79f248c37774d1dd761406f83d25ca6ff8e4≥ e48354ce078c079996f89d715dfa44814b4eba01 and < 6ddddcad436d8e6e619204d3c848147ff2f5bf1e≥ e48354ce078c079996f89d715dfa44814b4eba01 and < b19dc17ed963ac36c0db4b52a1803fb11169f91f≥ e48354ce078c079996f89d715dfa44814b4eba01 and < 6b589ef9d5f6cdc70d2b4f269ca6cf26b5ebb076≥ e48354ce078c079996f89d715dfa44814b4eba01 and < eb9dadf4d552ebe10644871c5189286552aa48f5≥ e48354ce078c079996f89d715dfa44814b4eba01 and < 1624bff4c5118ad494d50ad94d44f22064667a7f≥ e48354ce078c079996f89d715dfa44814b4eba01 and < 3ddf3ea291a0ef2ea93b82e158960ac2cc42302b≥ e48354ce078c079996f89d715dfa44814b4eba01 and < f4825922d2fb371e2b969697d792077f1b62b62c and 1 more version 3.1	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
9.1	CVSS 3.1	Critical	3.9	5.2	416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
9.1	CVSS 3.1	Critical	—	—	Linux via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · linux/linux
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
CVSS changed · 9.1
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Received
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Sep 16, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

8 on the record

git.kernel.org/stable/c/f4825922d2fb371e2b969697d792077f1b62b62c
NIST National Vulnerability Database
git.kernel.org/stable/c/3ddf3ea291a0ef2ea93b82e158960ac2cc42302b
NIST National Vulnerability Database
git.kernel.org/stable/c/eb9dadf4d552ebe10644871c5189286552aa48f5
NIST National Vulnerability Database
git.kernel.org/stable/c/6ddddcad436d8e6e619204d3c848147ff2f5bf1e
NIST National Vulnerability Database
git.kernel.org/stable/c/b19dc17ed963ac36c0db4b52a1803fb11169f91f
NIST National Vulnerability Database
git.kernel.org/stable/c/5fac79f248c37774d1dd761406f83d25ca6ff8e4
NIST National Vulnerability Database
git.kernel.org/stable/c/6b589ef9d5f6cdc70d2b4f269ca6cf26b5ebb076
NIST National Vulnerability Database
git.kernel.org/stable/c/1624bff4c5118ad494d50ad94d44f22064667a7f
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 13h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 13h
Unknown CVE-2026-98431 RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency 1d
Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-90011 is "scsi: target: iscsi: Reserve a terminator byte for the login payload", rated Critical. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.1 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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