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NVD / CVE Program· CNA Linux

CVE-2026-23220: ksmbd: fix infinite loop caused by next_smb2_rcv_hdr_off reset in error paths

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.13% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 010eb01ce23b34b50531448b0da391c7f05a72af, 5.15.203, 544adb0a6658ea1bff4064723761dbf05f95b1e2; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 010eb01ce23b34b50531448b0da391c7f05a72af, 5.15.203, 544adb0a6658ea1bff4064723761dbf05f95b1e2; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes 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: ksmbd: fix infinite loop caused by next_smb2_rcv_hdr_off reset in error paths The problem occurs when a signed request fails smb2 signature verification check. In __process_request(), if check_sign_req() returns an error, set_smb2_rsp_status(work, STATUS_ACCESS_DENIED) is called. set_smb2_rsp_status() set work->next_smb2_rcv_hdr_off as zero. By resetting next_smb2_rcv_hdr_off to zero, the pointer to the next command in the chain is lost. Consequently, is_chained_smb2_message() continues to point to the same request header instead of advancing. If the header's NextCommand field is non-zero, the function returns true, causing __handle_ksmbd_work() to repeatedly process the same failed request in an infinite loop. This results in the kernel log being flooded with "bad smb2 signature" messages and high CPU usage. This patch fixes the issue by changing the return value from SERVER_HANDLER_CONTINUE to SERVER_HANDLER_ABORT. This ensures that the processing loop terminates immediately rather than attempting to continue from an invalidated offset.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 18, 2026
Updated
Jun 17, 2026
EPSS
0.1% · 3th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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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.

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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 kernel5.15.145 and later · before 5.16
  • linux linux kernel6.1.71 and later · before 6.1.164
  • linux linux kernel6.6.1 and later · before 6.6.125
  • linux linux kernel6.7 and later · before 6.12.72
  • linux linux kernel6.13 and later · before 6.18.11
  • linux linux kernel6.19 and later · before 6.19.1
  • linux linux kernel6.6

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

    • 6.6affected
    • 4b9b7ea1ffb1e34f01fa5726d0c184931b9ba565 and later · before 544adb0a6658ea1bff4064723761dbf05f95b1e2affected · git
    • 943cebf9ea3415ddefcd670d24d8883e97ba3d60 and later · before fb3b66bd72deb5543addaefa67963b34fb163a7baffected · git
    • be0f89d4419dc5413a1cf06db3671c9949be0d52 and later · before 5accdc5b7f28a81bbc5880ac0b8886e60c86e8c8affected · git
    • be0f89d4419dc5413a1cf06db3671c9949be0d52 and later · before f7b1c2f5642bbd60b1beef1f3298cbac81eb232caffected · git
    • be0f89d4419dc5413a1cf06db3671c9949be0d52 and later · before 71b5e7c528315ca360a1825a4ad2f8ae48c5dc16affected · git
    • be0f89d4419dc5413a1cf06db3671c9949be0d52 and later · before 9135e791ec2709bcf0cda0335535c74762489498affected · git
    • be0f89d4419dc5413a1cf06db3671c9949be0d52 and later · before 010eb01ce23b34b50531448b0da391c7f05a72afaffected · git
    • 5.15.145 and later · before 5.15.203affected · semver
    • 6.1.71 and later · before 6.1.164affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.164-16.1.164-1
Debian:13linuxbefore 6.12.73-16.12.73-1
Debian:14linuxbefore 6.18.12-16.18.12-1
openSUSE:Tumbleweedkernel-sourcebefore 6.19.8-1.16.19.8-1.1

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-2025-71233Feb 18, 2026 · PCI: endpoint: Avoid creating sub-groups asynchronously
    22Monitor
  • ← EarlierCVE-2025-71237Feb 18, 2026 · nilfs2: Fix potential block overflow that cause system hang
    22Monitor
  • Later →CVE-2026-23221Feb 18, 2026 · bus: fsl-mc: fix use-after-free in driver_override_show()
    31Monitor

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 Linux010eb01ce23b34b50531448b0da391c7f05a72afVendor (CNA)
Linux Linux5.15.203Vendor (CNA)
Linux Linux544adb0a6658ea1bff4064723761dbf05f95b1e2Vendor (CNA)
Linux Linux5accdc5b7f28a81bbc5880ac0b8886e60c86e8c8Vendor (CNA)
Linux Linux6.1.164Vendor (CNA)
Linux Linux71b5e7c528315ca360a1825a4ad2f8ae48c5dc16Vendor (CNA)
Linux Linux9135e791ec2709bcf0cda0335535c74762489498Vendor (CNA)
Linux Linuxf7b1c2f5642bbd60b1beef1f3298cbac81eb232cVendor (CNA)
Linux Linuxfb3b66bd72deb5543addaefa67963b34fb163a7bVendor (CNA)
cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0Release NotesMicrosoft (MSRC)
debian:linux6.1.164-1 · Debian:12Package registry (OSV)
opensuse:kernel-source6.19.8-1.1 · openSUSE:TumbleweedPackage registry (OSV)

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-2026-3144863 days apartext4: avoid infinite loops caused by residual data
    37Monitor
  • CVE-2026-63889151 days apartscsi: scsi_transport_fc: Widen FPIN pname walker counter to u32
    32Monitor
  • CVE-2026-52933126 days apartio_uring/poll: fix signed comparison in io_poll_get_ownership()
    31Monitor
  • CVE-2026-2345144 days apartbonding: prevent potential infinite loop in bond_header_parse()
    30Monitor
  • CVE-2026-3155265 days apartwifi: wlcore: Return -ENOMEM instead of -EAGAIN if there is not enough headroom
    30Monitor
  • CVE-2026-4605298 days apartceph: only d_add() negative dentries when they are unhashed
    30Monitor

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

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-835 · Loop with Unreachable Exit Condition ('Infinite Loop')

CVSS vector

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

nvd-primary

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. Fix✗ → ✓

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

References

Show all references (7 more)

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

All records