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CVE
CVE-2026-40262
Note Mark is an open-source note-taking application. In versions 0.19.1 and prior, the asset delivery handler serves upl
Note Mark is an open-source note-taking application. In versions 0.19.1 and prior, the asset delivery handler serves uploaded files inline and relies on magic-byte detection for content type, which does not identify text-based formats such as HTML, SVG, or XHTML. These files are served with an empty Content-Type, no X-Content-Type-Options: nosniff header, and inline disposition, allowing browsers to sniff and render active content.
An authenticated user can upload an HTML or SVG file containing JavaScript as a note asset, and when a victim navigates to the asset URL, the script executes under the application's origin with access to the victim's authenticated session and API actions. This issue has been fixed in version 0.19.2.
HIGH · CVSS 8.7
EPSS 0.00012
EPSS exploitation odds0.01% · top 98%
Schedule remediation
- CVSS base score ≥ 7.0
No Sigma yet — build one →
YARA rules0
Look this up elsewhere - one-click external pivots
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How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2026-40262, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
EPSS exploitation probability
0.01%
Top 98%odds of exploitation in the next 30 days
CVSS metric silhouette
shape grows toward worst-case
SSVC triage · cisa-vulnrichment
Exploitation
poc
Automatable
no
Tech impact
total
CVSS vector breakdown
Exploitability - how they get in
Attack Vector
Network
Adjacent
Local
Physical
Attack Complexity
Low
High
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Impact - what breaks
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
VECTOR
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N◆
ATT&CK techniques
2Techniques this CVE enables - linked via CWE → CAPEC → ATT&CK. Pills with a solid outline are named directly in ATT&CK or Nuclei templates (high confidence); the others are linked through weakness mappings.
▤ Build a SIEM detection for these techniques▤
CAPEC attack patterns
7Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.
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Weakness Classification
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Affected Packages
1Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Go
github.com/enchant97/note-mark/backend
HIGH
fixed in 0.0.0-20260411145018-6bb62842ccb9
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Related CVEs
8CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row. Not a guess.
CVE-1999-0036
IRIX login program with a nonzero LOCKOUT parameter allows creation or damage to...
same CWE-434
HIGH
CVE-2001-0340
An interaction between the Outlook Web Access (OWA) service in Microsoft Exchang...
same CWE-434
CVE-2001-1099
The default configuration of Norton AntiVirus for Microsoft Exchange 2000 2.x al...
same CWE-434
CVE-2001-0901
Hypermail allows remote attackers to execute arbitrary commands on a server supp...
same CWE-434
CVE-2000-1205
Cross site scripting vulnerabilities in Apache 1.3.0 through 1.3.11 allow remote...
same CWE-79
CVE-2002-0270
Opera, when configured with the "Determine action by MIME type" option disabled,...
same CWE-79
CVE-2002-1651
Cross-site scripting (XSS) vulnerability in Verity Search97 allows remote attack...
same CWE-79
CVE-2002-1700
Cross-site scripting vulnerability (XSS) in the missing template handler in Macr...
same CWE-79
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References & Sources
3Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.