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Fencer Vulns
medium 6.5

CVE-2026-58649 json

.NET Information Disclosure Vulnerability

published 2026-09-08 2 mo ago modified 2026-10-31 8 d ago also EUVD-2026-73722

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits
0
none known

Summary

Origin validation error in .NET allows an unauthorized attacker to disclose information over a network.

Patch / fix

  • Microsoft .NET 10.0 runtime 10.0.111, 10.0.400
  • Microsoft .NET 11.0 runtime 11.0 RC1
  • Microsoft .NET 8.0 runtime 8.0.130, 8.0.424
  • Microsoft .NET 9.0 runtime 9.0.120, 9.0.317
  • Microsoft Microsoft Visual Studio 2022 version 17.14 17.14.40
  • Microsoft Microsoft Visual Studio 2026 version 18.9 18.9.3
  • dotnet8 Ubuntu 22.04 LTS 8.0.131-8.0.31-0ubuntu1~22.04.1
  • dotnet8 Ubuntu 24.04 LTS 8.0.131-8.0.31-0ubuntu1~24.04.1
  • dotnet10 Ubuntu 24.04 LTS 10.0.112-10.0.12-0ubuntu1~24.04.1
  • dotnet10 Ubuntu 26.04 LTS 10.0.112-10.0.12-0ubuntu1~26.04.1

ubuntu advisories UBUNTU-CVE-2026-58649

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • dotnet8.0 hummingbird 1 8.0.131-0.1.hum1
  • dotnet-sdk-8.0 hummingbird 1 8.0.131-0.1.hum1
  • dotnet-sdk-dbg-8.0 hummingbird 1 8.0.131-0.1.hum1
  • dotnet-templates-8.0 hummingbird 1 8.0.131-0.1.hum1
  • dotnet-sdk-8.0-source-built-artifacts hummingbird 1 8.0.131-0.1.hum1
  • dotnet9.0 hummingbird 1 9.0.121-0.1.hum1
  • dotnet-sdk-9.0 hummingbird 1 9.0.121-0.1.hum1
  • dotnet-sdk-aot-9.0 hummingbird 1 9.0.121-0.1.hum1

red hat advisories RHSA-2026:77004RHSA-2026:76978RHSA-2026:66863RHSA-2026:68676RHSA-2026:68316RHSA-2026:68233

  • dotnet AlmaLinux 8 10.0.112-1.el8_10
  • dotnet-host AlmaLinux 8 10.0.12-1.el8_10
  • dotnet-sdk-10.0 AlmaLinux 8 10.0.112-1.el8_10
  • dotnet-hostfxr-10.0 AlmaLinux 8 10.0.12-1.el8_10
  • dotnet-runtime-10.0 AlmaLinux 8 10.0.12-1.el8_10
  • dotnet-sdk-aot-10.0 AlmaLinux 8 10.0.112-1.el8_10
  • dotnet-sdk-dbg-10.0 AlmaLinux 8 10.0.112-1.el8_10
  • dotnet-templates-10.0 AlmaLinux 8 10.0.112-1.el8_10

almalinux advisories ALSA-2026:68676ALSA-2026:68233ALSA-2026:68316ALSA-2026:67524ALSA-2026:67525ALSA-2026:67528

  • dotnet10.0 Rocky Linux 8 10.0.112-1.el8_10
  • dotnet9.0 Rocky Linux 8 9.0.121-1.el8_10
  • dotnet8.0 Rocky Linux 8 8.0.131-1.el8_10
  • dotnet8.0 Rocky Linux 10 8.0.131-1.el10_2
  • dotnet9.0 Rocky Linux 10 9.0.121-1.el10_2
  • dotnet10.0 Rocky Linux 10 10.0.112-1.el10_2
  • dotnet8.0 Rocky Linux 9 8.0.131-1.el9_8
  • dotnet10.0 Rocky Linux 9 10.0.112-1.el9_8

rocky linux advisories RLSA-2026:68676RLSA-2026:68233RLSA-2026:68316RLSA-2026:67525RLSA-2026:67528RLSA-2026:67530

  • dotnet8-runtime Alpine 3.24, Alpine 3.23, Alpine 3.22 8.0.31-r0
  • dotnet9-runtime Alpine 3.24, Alpine 3.23, Alpine 3.22 9.0.20-r0
  • dotnet10-runtime Alpine 3.23 10.0.13-r0
  • dotnet10-runtime Alpine 3.24 10.0.12-r0

alpine advisories ALPINE-CVE-2026-58649

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-58649 updated cvss 6.5

dotnet10.0: dotnet9.0: dotnet8.0: .NET Information Disclosure Vulnerability

  • Red Hat CodeReady Linux Builder EUS (v.9.6) dotnet-sdk-8.0-source-built-artifacts 8.0.132-1.el9_6, dotnet-sdk-9.0-source-built-artifacts 9.0.122-1.el9_6
    fixed: vendor fix RHSA-2026:88422
  • Red Hat Enterprise Linux AppStream (v. 8) dotnet 10.0.112-1.el8_10, dotnet8.0 8.0.131-1.el8_10, dotnet9.0 9.0.121-1.el8_10, dotnet-host 10.0.12-1.el8_10, dotnet10.0 10.0.112-1.el8_10, dotnet-sdk-8.0 8.0.131-1.el8_10, +35 more
    fixed: vendor fix RHSA-2026:68676
  • Red Hat Enterprise Linux AppStream (v. 9) dotnet8.0 8.0.131-1.el9_8, dotnet9.0 9.0.121-1.el9_8, dotnet-host 10.0.12-1.el9_8, dotnet10.0 10.0.112-1.el9_8, dotnet-sdk-8.0 8.0.131-1.el9_8, dotnet-sdk-9.0 9.0.121-1.el9_8, +34 more
    fixed: vendor fix RHSA-2026:67613
  • Red Hat Enterprise Linux AppStream (v. 10) dotnet8.0 8.0.131-1.el10_2, dotnet9.0 9.0.121-1.el10_2, dotnet-host 10.0.12-1.el10_2, dotnet10.0 10.0.112-1.el10_2, dotnet-sdk-8.0 8.0.131-1.el10_2, dotnet-sdk-9.0 9.0.121-1.el10_2, +34 more
    fixed: vendor fix RHSA-2026:67530
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) dotnet8.0 8.0.132-1.el9_4, dotnet-host 8.0.32-1.el9_4, dotnet-sdk-8.0 8.0.132-1.el9_4, dotnet-hostfxr-8.0 8.0.32-1.el9_4, dotnet-runtime-8.0 8.0.32-1.el9_4, dotnet-sdk-dbg-8.0 8.0.132-1.el9_4, +8 more
    fixed: vendor fix RHSA-2026:88425
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) dotnet8.0 8.0.132-1.el10_0, dotnet9.0 9.0.122-1.el10_0, dotnet-host 9.0.21-1.el10_0, dotnet-sdk-8.0 8.0.132-1.el10_0, dotnet-sdk-9.0 9.0.122-1.el10_0, dotnet-hostfxr-8.0 8.0.32-1.el10_0, +21 more
    fixed: vendor fix RHSA-2026:88474
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) dotnet8.0 8.0.132-1.el9_6, dotnet9.0 9.0.122-1.el9_6, dotnet-host 9.0.21-1.el9_6, dotnet-sdk-8.0 8.0.132-1.el9_6, dotnet-sdk-9.0 9.0.122-1.el9_6, dotnet-hostfxr-8.0 8.0.32-1.el9_6, +21 more
    fixed: vendor fix RHSA-2026:88422
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) dotnet-sdk-8.0-source-built-artifacts 8.0.131-1.el9_8, dotnet-sdk-9.0-source-built-artifacts 9.0.121-1.el9_8, dotnet-sdk-10.0-source-built-artifacts 10.0.112-1.el9_8
    fixed: vendor fix RHSA-2026:67613
show 5 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) dotnet-sdk-8.0-source-built-artifacts 8.0.131-1.el10_2, dotnet-sdk-9.0-source-built-artifacts 9.0.121-1.el10_2, dotnet-sdk-10.0-source-built-artifacts 10.0.112-1.el10_2
    fixed: vendor fix RHSA-2026:67530
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) dotnet-sdk-8.0-source-built-artifacts 8.0.132-1.el10_0, dotnet-sdk-9.0-source-built-artifacts 9.0.122-1.el10_0
    fixed: vendor fix RHSA-2026:88474
  • Red Hat Enterprise Linux CRB (v. 8) dotnet-sdk-8.0-source-built-artifacts 8.0.131-1.el8_10, dotnet-sdk-9.0-source-built-artifacts 9.0.121-1.el8_10, dotnet-sdk-10.0-source-built-artifacts 10.0.112-1.el8_10
    fixed: vendor fix RHSA-2026:68676
  • Red Hat Hardened Images dotnet10.0 10.0.112-1.hum1, dotnet8.0 8.0.131-0.1.hum1, dotnet9.0 9.0.121-0.1.hum1, dotnet-sdk-10.0 10.0.112-1.hum1, dotnet-sdk-8.0 8.0.131-0.1.hum1, dotnet-sdk-9.0 9.0.121-0.1.hum1, +12 more
    fixed: vendor fix RHSA-2026:66863
  • Red Hat Hardened Images dotnet-host 10.0.12-1.hum1, dotnet-hostfxr-10.0 10.0.12-1.hum1, dotnet-hostfxr-8.0 8.0.31-0.1.hum1, dotnet-hostfxr-9.0 9.0.20-0.1.hum1, dotnet-runtime-10.0 10.0.12-1.hum1, dotnet-runtime-8.0 8.0.31-0.1.hum1, +19 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Affected products

  • Microsoft .NET 10.0 runtime
  • Microsoft .NET 11.0 runtime
  • Microsoft .NET 8.0 runtime
  • Microsoft .NET 9.0 runtime
  • Microsoft Microsoft Visual Studio 2022 version 17.14
  • Microsoft Microsoft Visual Studio 2026 version 18.9

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.