.NET Denial of Service Vulnerability
- Exploited
- No known exploitation
- Fix
- Fixed in 11.0.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 11.0.0.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 38/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
Inefficient algorithmic complexity in .NET allows an unauthorized attacker to deny service over a network.
cve.now Index
- Exploitation0/40No signal
- Exposure20/25No login or user action needed per the CVSS vector, CISA rates it automatable · Unknown: No advisory context yet
- Reach10/20Affects NuGet packages
- Severity7.5/10CVSS 7.5
- No patch0/5No signal
What would change the score
- Would score about 83 if added to CISA KEV
- Would score about 78 if CISA's SSVC rates exploitation active
- Would score about 43 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 11.0.0.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-118747 (.NET Denial of Service Vulnerability), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-118747 (entry last updated 2026-11-10): Affected: - Microsoft System.Formats.Cbor: from 10.0.0, fixed in 11.0.0 - NuGet package System.Formats.Cbor: from 8.0.0-0, fixed in 8.0.2 - NuGet package System.Formats.Cbor: from 9.0.0-0, fixed in 9.0.24 - NuGet package System.Formats.Cbor: from 10.0.0-0, fixed in 10.0.15 - NuGet package System.Formats.Cbor: from 11.0.0-0, fixed in 11.0.0 Fixed versions: 11.0.0. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-118747 is not listed as of cve.now's last read. This KEV status is for CVE-2026-118747 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Packages (NuGet): find every lockfile in each project and run check_stack from the cve.now MCP server on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies. Verify against the linked advisories before concluding, and cite the date you read each one: - https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-118747 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-118747 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-118747.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
- First seen by cve.now
Affected versions
- Microsoft System.Formats.Cbor
From 10.0.0 · fixed in 11.0.0
- System.Formats.CborNuGet
From 8.0.0-0 · fixed in 8.0.2
- System.Formats.CborNuGet
From 9.0.0-0 · fixed in 9.0.24
- System.Formats.CborNuGet
From 10.0.0-0 · fixed in 10.0.15
- System.Formats.CborNuGet
From 11.0.0-0 · fixed in 11.0.0
Evidence 3
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Patch
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Corrections
None so far.
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Questions about CVE-2026-118747
Is CVE-2026-118747 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-118747?
System.Formats.Cbor: from 10.0.0 before 11.0.0. System.Formats.Cbor (NuGet): from 8.0.0-0 before 8.0.2. System.Formats.Cbor (NuGet): from 9.0.0-0 before 9.0.24. System.Formats.Cbor (NuGet): from 10.0.0-0 before 10.0.15. System.Formats.Cbor (NuGet): from 11.0.0-0 before 11.0.0.Source: cve.now feed data
How do I fix CVE-2026-118747?
Upgrade to a fixed version: 11.0.0.Source: cve.now feed data