Threats / SmarterTools / CVE-2025-52691
CVE-2025-52691
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
SmarterTools SmarterMail vulnerability
SmarterMail contains an unrestricted file upload vulnerability allowing unauthenticated attackers to upload arbitrary files, potentially enabling remote code execution on mail servers.
Verdict
Today item, not a backlog item.
An unauthenticated attacker can exploit CWE-434 to upload malicious files without restriction, achieving code execution on affected SmarterMail instances. Active exploitation and ransomware campaigns confirm critical risk.
CISA KEV Yes · 2026-01-265Ransomware use Flagged5EPSS 0.85457 (verify live)6Exploit Weaponized · public PoC7CVSS 103CISA SSVC Exploitation: active · Automatable: yes · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
15 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-01-26), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.85457 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 10 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H) · Affected: SmarterTools, SmarterMail. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 3.1, set at disclosure.
Weakness (CWE)
Mapped to CWE-434 Unrestricted File Upload — weakness family: Path traversal / file.CWE assignment from the public NVD record (may be stale); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 28 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
Public exploit available
Public exploit tooling is catalogued for this CVE (a functional/weaponized public exploit). Catalog entries: Metasploit module, nuclei template. We link the catalog page(s) only — no payload or code is hosted or restated here.Link, never host — the catalog page is the source; basicsecurity.net does not redistribute payloads.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious file and send an HTTP request to the vulnerable upload endpoint without authentication.
Business
The organization's mail server is immediately accessible to external threat actors without credential requirements.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I upload a web shell or executable to an arbitrary location on the server filesystem.
Business
Attackers gain persistent code execution capability within the mail infrastructure.
3
Lateral reach — past segmentation narrative 3
Attacker
I execute commands on the compromised server to establish lateral movement and data exfiltration.
Business
Email data, user credentials, and sensitive communications are exposed to theft and manipulation.
4
Data at risk — exfiltration narrative 4
Attacker
I deploy ransomware payloads across the mail server and connected systems.
Business
Critical business operations halt; ransom demands follow with threat of data publication.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05
Coverage & confidence
— what we know, and what we don’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by CSACNA
Credited with finding itChua Meng Hanfinder