Skip to content
Noroxi
NVD / CVE Program· CNA Linux

CVE-2026-53176: IB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN

Noroxi assessment

Priority: Monitor (action score 39/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.76% (FIRST EPSS); higher than 55.2% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 1ca40b243277c9e88be5e00bd3e083f71aefb93e, 29e7b925ae6df64894e82ab6419994dc25580a8a, 75ee6e4aa096aa9e7b2dd5c8ff98356e30aceefb; azl3 kernel 6.6.141.1-1 on Azure Linux 3.0 6.6.143.1-1.

Low priority for now. Upgrade to Linux Linux 1ca40b243277c9e88be5e00bd3e083f71aefb93e, 29e7b925ae6df64894e82ab6419994dc25580a8a, 75ee6e4aa096aa9e7b2dd5c8ff98356e30aceefb; azl3 kernel 6.6.141.1-1 on Azure Linux 3.0 6.6.143.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: IB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN In drivers/infiniband/ulp/isert/ib_isert.c, isert_login_recv_done() computes the login request payload length as wc->byte_len minus ISER_HEADERS_LEN with no lower bound, and login_req_len is a signed int. A remote iSER initiator can post a login Send work request carrying fewer than ISER_HEADERS_LEN (76) bytes, so the subtraction underflows and login_req_len becomes negative. isert_rx_login_req() then reads that negative length back into a signed int, takes size = min(rx_buflen, MAX_KEY_VALUE_PAIRS), and because the min() is signed it keeps the negative value; the value is then passed as the memcpy() length and sign-extended to a multi-gigabyte size_t. The copy into the 8192-byte login->req_buf runs far out of bounds and faults, crashing the target node. The login phase precedes iSCSI authentication, so no credentials are required to reach this path. Reject any login PDU shorter than ISER_HEADERS_LEN before the subtraction, mirroring the existing early return on a failed work completion, so login_req_len can never go negative. The upper bound was already safe: a posted login buffer cannot deliver more than ISER_RX_PAYLOAD_SIZE, so the difference stays at or below MAX_KEY_VALUE_PAIRS and the existing min() clamps it; only the missing lower bound needs to be added.

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Jun 25, 2026
Updated
Oct 19, 2026
EPSS
0.7% · 55th percentile

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.7%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
9.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-53176

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for linux records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel3.10 and later · before 5.10.259
  • linux linux kernel5.11 and later · before 5.15.210
  • linux linux kernel5.16 and later · before 6.1.176
  • linux linux kernel6.2 and later · before 6.6.143
  • linux linux kernel6.7 and later · before 6.12.94
  • linux linux kernel6.13 and later · before 6.18.36
  • linux linux kernel6.19 and later · before 7.0.13
  • linux linux kernel7.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 3.10affected
    • b8d26b3be8b33682cf163274ed07479a70554633 and later · before 75ee6e4aa096aa9e7b2dd5c8ff98356e30aceefbaffected · git
    • b8d26b3be8b33682cf163274ed07479a70554633 and later · before e8a013c0c3ca2f6708341a56612a3f6d6921620aaffected · git
    • b8d26b3be8b33682cf163274ed07479a70554633 and later · before bd22740d7f14cb1c0289444cfd2c8d2938667c1daffected · git
    • b8d26b3be8b33682cf163274ed07479a70554633 and later · before c1234229399f4af12c553b1b0ffd978eeba65548affected · git
    • b8d26b3be8b33682cf163274ed07479a70554633 and later · before c5584e089b5af7b3bf8bd5e8ca0560cbf32b0a47affected · git
    • b8d26b3be8b33682cf163274ed07479a70554633 and later · before df422fd273c96c2ee5beb80fc21adc8c70c29260affected · git
    • b8d26b3be8b33682cf163274ed07479a70554633 and later · before 1ca40b243277c9e88be5e00bd3e083f71aefb93eaffected · git
    • b8d26b3be8b33682cf163274ed07479a70554633 and later · before 29e7b925ae6df64894e82ab6419994dc25580a8aaffected · git
    • before 3.10not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.56.1.el10_26.12.0-211.56.1.el10_2

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-53167Jun 25, 2026 · fuse: limit FUSE_NOTIFY_RETRIEVE to uptodate folios
    22Monitor
  • ← EarlierCVE-2026-53168Jun 25, 2026 · fuse: reject fuse_notify() pagecache ops on directories
    22Monitor
  • Later →CVE-2026-53177Jun 25, 2026 · bnxt_en: Fix NULL pointer dereference
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux1ca40b243277c9e88be5e00bd3e083f71aefb93eVendor (CNA)
Linux Linux29e7b925ae6df64894e82ab6419994dc25580a8aVendor (CNA)
Linux Linux75ee6e4aa096aa9e7b2dd5c8ff98356e30aceefbVendor (CNA)
Linux Linuxbd22740d7f14cb1c0289444cfd2c8d2938667c1dVendor (CNA)
Linux Linuxc1234229399f4af12c553b1b0ffd978eeba65548Vendor (CNA)
Linux Linuxc5584e089b5af7b3bf8bd5e8ca0560cbf32b0a47Vendor (CNA)
Linux Linuxdf422fd273c96c2ee5beb80fc21adc8c70c29260Vendor (CNA)
Linux Linuxe8a013c0c3ca2f6708341a56612a3f6d6921620aVendor (CNA)
azl3 kernel 6.6.141.1-1 on Azure Linux 3.06.6.143.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:kernel6.12.0-211.56.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k6.12.0-211.56.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-core6.12.0-211.56.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug6.12.0-211.56.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-core6.12.0-211.56.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel6.12.0-211.56.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched6.12.0-211.56.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules6.12.0-211.56.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-core6.12.0-211.56.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra6.12.0-211.56.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel6.12.0-211.56.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel-matched6.12.0-211.56.1.el10_2 · AlmaLinux:10Package registry (OSV)
debian:linux6.1.176-1 · Debian:12Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:6.12.0-211.56.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel0:6.12.0-211.56.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel-matched0:6.12.0-211.56.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debuginfo0:6.12.0-211.56.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel0:6.12.0-211.56.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel-matched0:6.12.0-211.56.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-debuginfo0:6.12.0-211.56.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel0:6.12.0-211.56.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)

+6

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-6394024 days apartKVM: SEV: Ignore Port I/O requests of length '0'
    37Monitor
  • CVE-2026-4318750 days apartxfs: delete attr leaf freemap entries when empty
    35Monitor
  • CVE-2026-531780 days apartstaging: rtl8723bs: rtw_mlme: add bounds checks before ie_length subtraction
    32Monitor
  • CVE-2026-529191 days apartbatman-adv: fix tp_meter counter underflow during shutdown
    31Monitor
  • CVE-2026-531301 days apartfs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START
    31Monitor
  • CVE-2026-4610728 days apartdm-thin: fix metadata refcount underflow
    31Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-191 · Integer Underflow (Wrap or Wraparound)

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (14 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records