Home/CVE/Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, when a WebSocket connection was opened, Deno
CVE
CVE-2026-49860
Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, when a WebSocket connection was opened, Deno
Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, when a WebSocket connection was opened, Deno checked the destination hostname against --deny-net rules but did not re-check the IP addresses that hostname resolved to. An attacker-controlled script could use a specially crafted domain name that passes the hostname check yet resolves to a denied IP, bypassing the network restriction entirely.
This vulnerability is fixed in 2.8.1.
MEDIUM · CVSS 5.2
Monitor
- No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
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-2026-49860, 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
n/a
No EPSS score in our data for this CVE. EPSS is published daily for scored CVEs - a very new, reserved, or rejected CVE may not have one yet.
CVSS metric silhouette
shape grows toward worst-case
SSVC triage
No SSVC vulnrichment for this CVE. CISA's Vulnrichment program scores newer CVEs (~2024 onwards) plus selected older critical ones. Use the EPSS probability + KEV status to triage instead.
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:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N◆
ATT&CK techniques
1Techniques this CVE enables. Pills with a solid outline are high confidence - named directly in ATT&CK or Nuclei, or human-curated by CTID; the rest are inferred from the weakness type using MITRE's CVE Mapping Methodology and the CWE → CAPEC chain. Broad, generic-weakness guesses are filtered out. A small N× marks a technique that N independent sources agree on.
▤ Build a SIEM detection for these techniques▤
CAPEC attack patterns
1Attack 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.
crates.io
deno
MODERATE
fixed in 2.8.1
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Related CVEs
4CVEs 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.
CVE-2002-1484
DB4Web server, when configured to use verbose debug messages, allows remote atta...
1
same CWE-918
CRITICAL
CVE-2004-2061
RiSearch 1.0.01 and RiSearch Pro 3.2.06 allows remote attackers to use the show....
2
same CWE-918
CRITICAL
CVE-2007-6758
Server-side request forgery (SSRF) vulnerability in feed-proxy.php in extjs 5.0....
same CWE-918
HIGH
CVE-2010-1637
The Mail Fetch plugin in SquirrelMail 1.4.20 and earlier allows remote authentic...
same CWE-918
MEDIUM
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References & Sources
1Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.