Vulnerability in Linux kernel (CVE-2026-90413)
Summary
Vulnerability in Linux kernel (CVE-2026-90413). Confidential information can be exposed externally.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
IB/isert: reject login PDUs declaring more data than was received
isert_login_recv_done() records how many bytes the HCA actually placed in
the login buffer, but nothing compares that against the length the login
PDU's BHS declares. isert_rx_login_req() copies min(login_req_len,
MAX_KEY_VALUE_PAIRS) bytes into login->req_buf, and the login code then
reads the declared length back out of that buffer - for the first PDU in
iscsi_target_locate_portal(),
payload_length = ntoh24(login_req->dlength);
tmpbuf = kmemdup_nul(login->req_buf, payload_length, GFP_KERNEL);
and for the ones after it in iscsi_decode_text_input(), reached from
iscsi_target_do_login().
login->req_buf is a fixed MAX_KEY_VALUE_PAIRS (8192) byte allocation, so
an initiator that declares more than it sends reads off the end of it,
before authentication and with the length under its control:
BUG: KASAN: slab-out-of-bounds in kmemdup_nul+0x43/0x80
Read of size 8193 at addr ffff8881056a8000 by task iscsi_np/167
__asan_memcpy+0x23/0x60
kmemdup_nul+0x43/0x80
iscsi_target_locate_portal+0x48d/0x1180
iscsi_target_login_thread+0x19a9/0x3350
Allocated by task 167:
__kmalloc_cache_noprof+0x158/0x370
iscsi_target_login_thread+0x971/0x3350
which belongs to the cache kmalloc-8k of size 8192
allocated 8192-byte region
Falsifying the second login PDU instead reaches the other reader, on the
same buffer:
BUG: KASAN: slab-ou…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-90413 has been found in Linux kernel.
Confidential information can be exposed externally. CVSS score: 9.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-90413" on the vendor's site.
CVE-2026-90413 (Linux kernel) — CVSS v3 9.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: Critical (CVSS 9.1/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-90413 linux Fixed in: 6.1.190-1
- Ubuntu UBUNTU-CVE-2026-90413 linux
References
- advisory nvd.nist.gov
- advisory github.com
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web github.com