#microsoft

# Microsoft Security Advisory CVE-2025-21171 | .NET Remote Code Execution Vulnerability ## <a name="executive-summary"></a>Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 9.0. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. An attacker could exploit this vulnerability by sending a specially crafted request to the vulnerable web server. ## Announcement Announcement for this issue can be found at https://github.com/dotnet/runtime/issues/111423 ## <a name="mitigation-factors"></a>Mitigation factors Microsoft has not identified any mitigating factors for this vulnerability. ## <a name="affected-software"></a>Affected software * Any .NET 9.0 application running on .NET 9.0.0 or earlier. ## <a name="affected-packages"></a>Affected Packages The vulnerability affects any Microsoft .NET project if it uses any of affected packages versions list...

### Description The [Git credential protocol](https://git-scm.com/docs/git-credential#IOFMT) is text-based over standard input/output, and consists of a series of lines of key-value pairs in the format `key=value`. Git's documentation restricts the use of the NUL (`\0`) character and newlines to form part of the keys[^1] or values. When Git reads from standard input, it considers both LF and CRLF[^2] as newline characters for the credential protocol by virtue of [calling `strbuf_getline`](https://github.com/git/git/blob/6a11438f43469f3815f2f0fc997bd45792ff04c0/credential.c#L311) that calls to `strbuf_getdelim_strip_crlf`. Git also validates that a newline is not present in the value by checking for the presence of the line-feed character (LF, `\n`), and errors if this is the case. This captures both LF and CRLF-type newlines. Git Credential Manager uses the .NET standard library [`StreamReader`](https://learn.microsoft.com/en-us/dotnet/api/system.io.streamreader?view=net-8.0) class t...

Microsoft has shed light on a now-patched security flaw impacting Apple macOS that, if successfully exploited, could have allowed an attacker running as "root" to bypass the operating system's System Integrity Protection (SIP) and install malicious kernel drivers by loading third-party kernel extensions. The vulnerability in question is CVE-2024-44243 (CVSS score: 5.5), a medium-severity bug

**The Security Updates table indicates that this vulnerability affects all supported versions of Microsoft Windows. Why are IE Cumulative updates listed for Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, and Windows Server 2012 R2?** While Microsoft has announced retirement of the Internet Explorer 11 application on certain platforms and the Microsoft Edge Legacy application is deprecated, the underlying MSHTML, EdgeHTML, and scripting platforms are still supported. The MSHTML platform is used by Internet Explorer mode in Microsoft Edge as well as other applications through WebBrowser control. The EdgeHTML platform is used by WebView and some UWP applications. The scripting platforms are used by MSHTML and EdgeHTML but can also be used by other legacy applications. Updates to address vulnerabilities in the MSHTML platform and scripting engine are included in the IE Cumulative Updates; EdgeHTML and Chakra changes are not applicable to those platforms. To stay fully ...

**How could an attacker exploit this vulnerability?** The attacker would be able to bypass the protection in Outlook that prevents a potentially dangerous file extension from being attached enabling a remote code execution.

**According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution?** The word **Remote** in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). The attack itself is carried out locally. For example, when the score indicates that the **Attack Vector** is **Local** and **User Interaction** is **Required**, this could describe an exploit in which an attacker, through social engineering, convinces a victim to download and open a specially crafted file from a website which leads to a local attack on their computer.

**What privileges could be gained by an attacker who successfully exploited the vulnerability?** An attacker who successfully exploits this vulnerability could elevate their privileges to perform commands as Root in the target environment.

**According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?** Successful exploitation of this vulnerability requires an attacker to win a race condition.

**According to the CVSS metric, successful exploitation of this vulnerability has a high impact on availability (A:H). What does that mean for this vulnerability??** An attacker can send specially crafted packets which could impact availability of the service resulting in Denial of Service (DoS).

**According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution?** The word **Remote** in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). The attack itself is carried out locally. For example, when the score indicates that the **Attack Vector** is **Local** and **User Interaction** is **Required**, this could describe an exploit in which an attacker, through social engineering, convinces a victim to download and open a specially crafted file from a website which leads to a local attack on their computer.