CVE-2026-45491
published 2026-06-09CVE-2026-45491: Improper link resolution before file access ('link following') in .NET allows an unauthorized attacker to perform tampering locally.
PriorityP430medium6.2CVSS 3.1
AVLACLPRNUINSUCNIHAN
EPSS
0.39%
31.1th percentile
Improper link resolution before file access ('link following') in .NET allows an unauthorized attacker to perform tampering locally.
Affected
16 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | microsoft.netcore.app.runtime.linux-x64 | >= 10.0.0 < 10.0.9 | 10.0.9 |
| microsoft | microsoft.netcore.app.runtime.linux-x64 | >= 8.0.0 < 8.0.28 | 8.0.28 |
| microsoft | microsoft.netcore.app.runtime.linux-x64 | >= 9.0.0 < 9.0.17 | 9.0.17 |
| microsoft | microsoft.netcore.app.runtime.osx-arm64 | >= 10.0.0 < 10.0.9 | 10.0.9 |
| microsoft | microsoft.netcore.app.runtime.osx-arm64 | >= 8.0.0 < 8.0.28 | 8.0.28 |
| microsoft | microsoft.netcore.app.runtime.osx-arm64 | >= 9.0.0 < 9.0.17 | 9.0.17 |
| microsoft | microsoft.netcore.app.runtime.win-x64 | >= 10.0.0 < 10.0.9 | 10.0.9 |
| microsoft | microsoft.netcore.app.runtime.win-x64 | >= 8.0.0 < 8.0.28 | 8.0.28 |
| microsoft | microsoft.netcore.app.runtime.win-x64 | >= 9.0.0 < 9.0.17 | 9.0.17 |
| microsoft | net_10.0 | >= 10.0.0 < 10.0.9 | 10.0.9 |
| microsoft | net_8.0 | >= 8.0 < 8.0.28 | 8.0.28 |
| microsoft | net_8.0 | >= 8.0.0 < 8.0.28 | 8.0.28 |
| microsoft | net_9.0 | >= 9.0.0 < 9.0.17 | 9.0.17 |
| ubuntu | dotnet10 | — | — |
| ubuntu | dotnet8 | — | — |
| ubuntu | dotnet9 | — | — |
CVSS provenance
nvdv3.16.2MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
ghsa6.2MEDIUM
vendor_redhat6.2MEDIUM
vendor_ubuntu6.2MEDIUM
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Ubuntu
.NET vulnerabilities
vendor_ubuntu·2026-06-11·CVSS 6.2
CVE-2026-45491 [MEDIUM] .NET vulnerabilities
Title: .NET vulnerabilities
Summary: Several security issues were fixed in .NET.
It was discovered that .NET did not properly handle link resolution before
file access. A local attacker could use this issue to perform unauthorized
file tampering and write arbitrary files outside of the intended extraction
directory. (CVE-2026-45491)
It was discovered that .NET did not properly handle deeply-nested
MessagePack arrays. An attacker could use this to cause .NET to consume
excessive resources, resulting in a denial of service. (CVE-2026-45591)
Instructions: In general, a standard system update will make all the necessary changes.
Red Hat
dotnet: .NET: Local file tampering via link following vulnerability
vendor_redhat·2026-06-09·CVSS 6.2
CVE-2026-45491 [MEDIUM] CWE-59 dotnet: .NET: Local file tampering via link following vulnerability
dotnet: .NET: Local file tampering via link following vulnerability
Improper link resolution before file access ('link following') in .NET allows an unauthorized attacker to perform tampering locally.
A flaw was found in .NET. This vulnerability, related to improper link resolution before file access (also known as 'link following'), allows an unauthorized local attacker to perform unauthorized tampering. This could lead to integrity compromise of local files.
Package: dotnet10.0 (Red Hat Enterprise Linux 10) - Affected
Package: dotnet10.0 (Red Hat Enterprise Linux 9) - Affected
Package: dotnet8.0 (Red Hat Enterprise Linux 9) - Affected
Package: dotnet9.0 (Red Hat Enterprise Linux 9) - Affected
Package: dotnet10.0 (Red Hat Hardened Images) - Affected
Package: dotnet8.0 (Red Hat Har
GHSA
Microsoft Security Advisory CVE-2026-45491 – .NET Tampering Vulnerability
ghsa·2026-06-16·CVSS 6.2
CVE-2026-45491 [MEDIUM] CWE-59 Microsoft Security Advisory CVE-2026-45491 – .NET Tampering Vulnerability
Microsoft Security Advisory CVE-2026-45491 – .NET Tampering Vulnerability
## Executive Summary
Microsoft is releasing this security advisory to provide information about a vulnerability in System.Formats.Tar. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
A tampering vulnerability exists in the `TarFile.ExtractToDirectory` method where a symlink path traversal enables an attacker to perform arbitrary file writes outside the intended extraction directory.
## Announcement
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/404
## Affected Platforms
- **Platforms:** All
- **Architectures:** All
## Affected Packages
The vulnerability affects any Microsoft .NET project if it
VulDB
Microsoft .NET prior 10.0.9 link following
vuldb·2026-06-09·CVSS 6.2
CVE-2026-45491 [MEDIUM] Microsoft .NET prior 10.0.9 link following
A vulnerability was found in Microsoft .NET. It has been rated as problematic. This vulnerability affects unknown code. This manipulation causes link following.
This vulnerability is handled as CVE-2026-45491. It is possible to launch the attack on the local host. There is not any exploit available.
Upgrading the affected component is advised.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-45491 dotnet10.0: .NET: Local file tampering via link following vulnerability [fedora-all]
bugzilla·2026-06-10·CVSS 6.2
CVE-2026-45491 [MEDIUM] CVE-2026-45491 dotnet10.0: .NET: Local file tampering via link following vulnerability [fedora-all]
CVE-2026-45491 dotnet10.0: .NET: Local file tampering via link following vulnerability [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-45491 dotnet9.0: .NET: Local file tampering via link following vulnerability [fedora-all]
bugzilla·2026-06-10·CVSS 6.2
CVE-2026-45491 [MEDIUM] CVE-2026-45491 dotnet9.0: .NET: Local file tampering via link following vulnerability [fedora-all]
CVE-2026-45491 dotnet9.0: .NET: Local file tampering via link following vulnerability [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-45491 dotnet8.0: .NET: Local file tampering via link following vulnerability [fedora-all]
bugzilla·2026-06-10·CVSS 6.2
CVE-2026-45491 [MEDIUM] CVE-2026-45491 dotnet8.0: .NET: Local file tampering via link following vulnerability [fedora-all]
CVE-2026-45491 dotnet8.0: .NET: Local file tampering via link following vulnerability [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-45491 dotnet: .NET: Local file tampering via link following vulnerability
bugzilla·2026-06-09·CVSS 6.2
CVE-2026-45491 [MEDIUM] CVE-2026-45491 dotnet: .NET: Local file tampering via link following vulnerability
CVE-2026-45491 dotnet: .NET: Local file tampering via link following vulnerability
Improper link resolution before file access ('link following') in .NET allows an unauthorized attacker to perform tampering locally.
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 10
Via RHSA-2026:25111 https://access.redhat.com/errata/RHSA-2026:25111
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 10
Via RHSA-2026:25112 https://access.redhat.com/errata/RHSA-2026:25112
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 10
Via RHSA-2026:25115 https://access.redhat.com/errata/RHSA-2026:25115
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux
Sans Isc
Microsoft June 2026 Patch Tuesday, (Tue, Jun 9th)
blogs_sans_isc·2026-06-09·CVSS 8.8
CVE-2026-49160 [HIGH] Microsoft June 2026 Patch Tuesday, (Tue, Jun 9th)
Microsoft June 2026 Patch Tuesday
Published: 2026-06-09. Last Updated: 2026-06-09 17:34:29 UTC
by Johannes Ullrich (Version: 1)
0 comment(s)
Microsoft today released patches for 204 vulnerabilities. 38 of these vulnerabilities are considered critical, and three have been disclosed before today. Six of the vulnerabilities affect Microsoft cloud solutions and do not require any user action. In addition, Microsoft incorporated 360 different vulnerabilities affecting Chromium into its Edge browser.
This is certainly a busier-than-usual patch Tuesday. In particular, the large number of patched Chromium/Edge vulnerabilities underscores the impact of AI tools on vulnerability discovery.
Some noteworthy vulnerabilities:
CVE-2026-49160: This vulnerability was made public a week ago. As implem
Rapid7
Patch Tuesday - June 2026
blogs_rapid7·2026-06-09·CVSS 7.8
CVE-2026-33825 [HIGH] Patch Tuesday - June 2026
Microsoft is publishing 200 vulnerabilities on June 2026 Patch Tuesday . Microsoft is not aware of exploitation in the wild for any of these vulnerabilities, and is aware of public disclosure for three. This is similar to last month’s Patch Tuesday, however several of last month’s vulnerabilities ended up on CISA KEV in the days following their publication. So far this month, Microsoft has provided patches to address 360 browser vulnerabilities, which is an order of magnitude more than has been typical in any given month over the past few years. As usual, browser vulns are not included in the Patch Tuesday count above. Indeed, the vast, and presumably sustained, uptick in the number of browser vulnerabilities has led to Microsoft no longer enumerating Chromium CVEs in the Security Update G
Bleepingcomputer
Microsoft June 2026 Patch Tuesday fixes 3 zero-day, 200 flaws
blogs_bleepingcomputer·2026-06-09·CVSS 7.8
CVE-2026-45586 [HIGH] Microsoft June 2026 Patch Tuesday fixes 3 zero-day, 200 flaws
## Microsoft June 2026 Patch Tuesday fixes 3 zero-day, 200 flaws
## Lawrence Abrams
65 Elevation of Privilege Vulnerabilities
19 Security Feature Bypass Vulnerabilities
55 Remote Code Execution Vulnerabilities
30 Information Disclosure Vulnerabilities
7 Denial of Service Vulnerabilities
27 Spoofing Vulnerabilities
When BleepingComputer reports on Patch Tuesday security updates, we only count those released by Microsoft today.
Therefore, the number of flaws does not include flaws in Mariner, Azure HorizonDB, Microsoft Copilot, Copilot Chat, M365 Copilot, Microsoft Exchange Online, and Microsoft Graph that were fixed by Microsoft earlier this month.
There were also a massive 360 Microsoft Edge/Chromium flaws that were fixed by Google this month, which were excluded from this Patch
2026-06-09
Published