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NVD / CVE Program· CNA VulnCheck

CVE-2026-24423: SmarterTools SmarterMail < Build 9511 Unauthenticated RCE via ConnectToHub API

Noroxi assessment

Priority: Now (action score 93/100)

  • CISA has confirmed exploitation in the wild (Feb 5, 2026); it is known to be used in ransomware campaigns. Remediation deadline for US federal agencies: Feb 26, 2026.
  • A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
  • Probability of exploitation in the next 30 days: 88.1% (FIRST EPSS); higher than 99.7% 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: SmarterTools SmarterMail 100.0.9511.

Patch today or shut off access. Upgrade to SmarterTools SmarterMail 100.0.9511 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 · CISA KEV · FIRST EPSS

SmarterTools SmarterMail versions prior to build 9511 contain an unauthenticated remote code execution vulnerability in the ConnectToHub API method. The attacker could point the SmarterMail to the malicious HTTP server, which serves the malicious OS command. This command will be executed by the vulnerable application.

CriticalCVSS 9.3 · v4.0KEVWeaponized Fix available
Published
Jan 23, 2026
Updated
Aug 4, 2026
EPSS
88.1% · 99th percentile

Report tools

JSON

Action score

93

Now

Patch today or shut off access.

CVSS
37 / 40 · 9.3 / 10
CISA KEV
30 / 30 · Listed
EPSS
26 / 30 · 88.1%

CISA SSVC decision

Exploitation
active
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · VulnCheck
9.3
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Feb 5, 2026. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Feb 26, 2026.

Known to be used in ransomware campaigns.

Get told when this record changes

  • In CISA KEV: exploitation in the wild confirmed
  • Weaponized exploit exists
  • A fix has been released

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

Follow CVE-2026-24423

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

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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
smartertoolssmartermail

Affected versions

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

  • smartertools smartermailbefore 100.0.9511

Versions reported by the vendor

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

  • SmarterTools SmarterMail

    • before 100.0.9511affected · semver

Same product

smartertools: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-23760SmarterTools SmarterMail < Build 9511 Authentication Bypass via Password Reset APIKEV
    96Now
  • CVE-2025-52691Upload Arbitrary FilesKEV
    96Now
  • CVE-2019-7214SmarterTools SmarterMail 16.x before build 6985 allows deserialization of untrusted data.
    64This week

Published before and after this one in the same product

  • ← EarlierCVE-2023-48115Dec 21, 2023 · SmarterTools SmarterMail 8495 through 8664 before 8747 allows stored DOM XSS because an XSS protection mechanism is skipped when messageHTML
    21Monitor
  • ← EarlierCVE-2023-48116Dec 21, 2023 · SmarterTools SmarterMail 8495 through 8664 before 8747 allows stored XSS via a crafted description of a Calendar appointment.
    21Monitor
  • Later →CVE-2026-25067Jan 29, 2026 · SmarterTools SmarterMail < Build 9518 Unauthenticated background-of-the-day Path Coercion
    27Monitor

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
SmarterTools SmarterMail100.0.9511Vendor (CNA)

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×2

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Nuclei detection templateNuclei template CVE-2026-24423 —
Proof-of-concept repository on GitHubstars:92026-01-29
Proof-of-concept repository on GitHubstars:02026-09-02

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.

  1. Published
  2. First PoC+5 d
  3. CISA KEV+12 d
  4. TodayNov 8, 2026+289 d

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.

Variant candidates

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

—

Chain candidates

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

  • CVE-2026-7807105 days apartSmarterTools SmarterMail < Build 9560 Server Local File Inclusion via the /api/v1/report/summary/{type} API
    34Monitor

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
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-306 · Missing Authentication for Critical Function

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

A function added for development or support ships to production without authentication. It often relies on the assumption that it is “only reachable from the internal network.”

The bug in code

The whole CWE-306 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
// Added for the support teamapp.post("/maintenance/reset", resetDevice);

Fixed

ts
if (config.maintenanceEnabled) {  app.post(    "/maintenance/reset",    requireSession, requireRole("admin"), resetDevice  );}

Attack context

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (3 more)

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

All records