CVE-2026-21527
published 2026-02-10CVE-2026-21527: Microsoft Exchange Server Spoofing Vulnerability User interface (ui) misrepresentation of critical information in Microsoft Exchange Server allows an…
medium6.5CVSS 3.1
AVNACLPRNUINSUCLILAN
EPSS
7.68%
93.9th percentile
Microsoft Exchange Server Spoofing Vulnerability
User interface (ui) misrepresentation of critical information in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
Affected
10 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| github.com | gotenberg_gotenberg_v7 | 0 – 7.10.2 | — |
| github.com | gotenberg_gotenberg_v8 | >= 0 < 8.29.0 | 8.29.0 |
| microsoft | microsoft_exchange_server_2016_cumulative_update_23 | >= 15.01.0.0 < 15.01.2507.066 | 15.01.2507.066 |
| microsoft | microsoft_exchange_server_2019_cumulative_update_14 | >= 15.02.0.0 < 15.02.1544.039 | 15.02.1544.039 |
| microsoft | microsoft_exchange_server_2019_cumulative_update_15 | >= 15.02.0.0 < 15.02.1748.043 | 15.02.1748.043 |
| microsoft | microsoft_exchange_server_subscription_edition_rtm | >= 15.02.0.0 < 15.02.2562.037 | 15.02.2562.037 |
| msrc | microsoft_exchange_server_2016_cumulative_update_23 | — | — |
| msrc | microsoft_exchange_server_2019_cumulative_update_14 | — | — |
| msrc | microsoft_exchange_server_2019_cumulative_update_15 | — | — |
| msrc | microsoft_exchange_server_subscription_edition_rtm | — | — |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
cvelistv56.5MEDIUM
ghsa8.2HIGH
vendor_msrc6.5MEDIUM
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VulDB
Microsoft Exchange Server clickjacking
vuldb·2026-06-15·CVSS 6.5
CVE-2026-21527 [MEDIUM] Microsoft Exchange Server clickjacking
A vulnerability, which was classified as problematic, was found in Microsoft Exchange Server. This affects an unknown function. Executing a manipulation can lead to clickjacking.
This vulnerability appears as CVE-2026-21527. The attack may be performed from remote. There is no available exploit.
A patch should be applied to remediate this issue.
GHSA
Gotenberg has Chromium deny-list bypass via case-insensitive URL scheme (bypass of GHSA-rh2x-ccvw-q7r3)
ghsa·2026-03-30·CVSS 8.2
CVE-2026-27018 [HIGH] CWE-22 Gotenberg has Chromium deny-list bypass via case-insensitive URL scheme (bypass of GHSA-rh2x-ccvw-q7r3)
Gotenberg has Chromium deny-list bypass via case-insensitive URL scheme (bypass of GHSA-rh2x-ccvw-q7r3)
### Impact
The fix introduced in version 8.1.0 for GHSA-rh2x-ccvw-q7r3 (CVE-2024-21527) can be bypassed using mixed-case or uppercase URL schemes.
The default `--chromium-deny-list` value is `^file:(?!//\/tmp/).*`. This regex is anchored to lowercase `file:` at the start. However, per RFC 3986 Section 3.1, URI schemes are case-insensitive. Chromium normalizes the scheme to lowercase before navigation, so a URL like `FILE:///etc/passwd` or `File:///etc/passwd` bypasses the deny-list check but still gets resolved by Chromium as `file:///etc/passwd`.
The root cause is in `pkg/gotenberg/filter.go` — the `FilterDeadline` function compiles the deny-list regex with `regexp2.MustCompile(deni
CVEList
Microsoft Exchange Server Spoofing Vulnerability
cvelistv5·2026-02-10·CVSS 6.5
CVE-2026-21527 [MEDIUM] CWE-451 Microsoft Exchange Server Spoofing Vulnerability
Microsoft Exchange Server Spoofing Vulnerability
User interface (ui) misrepresentation of critical information in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
Microsoft
Microsoft Exchange Server Spoofing Vulnerability
vendor_msrc·2026-02-10·CVSS 6.5
CVE-2026-21527 [MEDIUM] CWE-451 Microsoft Exchange Server Spoofing Vulnerability
Microsoft Exchange Server Spoofing Vulnerability
Description: User interface (ui) misrepresentation of critical information in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
FAQ: According to the CVSS metrics, successful exploitation of this vulnerability could lead to some loss of confidentiality (C:L), and integrity (I:L) but lead to no loss of availability (A:N). What is the impact of this vulnerability?
An attacker who successfully exploited the vulnerability could view some sensitive information (Confidentiality), make changes to disclosed information (Integrity), but cannot limit access to the resource (Availability).
FAQ: Why are update links missing for some Exchange products?
For Exchange Server 2016 and 2019, update links are not
No detection rules found.
No public exploits indexed.
Sophos
February’s Patch Tuesday assumes battle stations
blogs_sophos·2026-02-13
February’s Patch Tuesday assumes battle stations
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Qualys
Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review
blogs_qualys·2026-02-10
Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review
## Table of Contents
Microsoft Patch Tuesday forFebruary2026
Adobe Patches for February 2026
Zero-day Vulnerabilities Patched inFebruaryPatch Tuesday Edition
Critical Severity Vulnerabilities Patched inFebruaryPatch Tuesday Edition
Other Microsoft Vulnerability Highlights
Microsoft Release Summary
Discover and Prioritize Vulnerabilities inVulnerability Management, Detection & Response (VMDR)
Rapid Response with TruRisk Eliminate
Qualys Monthly Webinar Series
Microsoft’s February 2026 Patch Tuesday focuses on closing security gaps that attackers could exploit, reinforcing the importance of timely patching in enterprise environments. Here’s a quick breakdown of what you need to know.
## Microsoft Patch Tuesday for February 2026
This month’s release addresses 61 vulnerabilities, i
Bleepingcomputer
Microsoft February 2026 Patch Tuesday fixes 6 zero-days, 58 flaws
blogs_bleepingcomputer·2026-02-10·CVSS 8.8
[HIGH] Microsoft February 2026 Patch Tuesday fixes 6 zero-days, 58 flaws
## Microsoft February 2026 Patch Tuesday fixes 6 zero-days, 58 flaws
## Lawrence Abrams
25 Elevation of Privilege vulnerabilities
5 Security Feature Bypass vulnerabilities
12 Remote Code Execution vulnerabilities
6 Information Disclosure vulnerabilities
3 Denial of Service vulnerabilities
7 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 3 Microsoft Edge flaws fixed earlier this month.
As part of these updates, Microsoft has also begun to roll out updated Secure Boot certificates to replace the original 2011 certificates that are expiring in late June 2026.
"With this update, Windows quality updates include a broad set of targeting data that i
Qualys
Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review | Qualys
blogs_qualys·2026-02-10
Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review | Qualys
#### Table of Contents
- Microsoft Patch Tuesday forFebruary2026
- Adobe Patches for February 2026
- Zero-day Vulnerabilities Patched inFebruaryPatch Tuesday Edition
- Critical Severity Vulnerabilities Patched inFebruaryPatch Tuesday Edition
- Other Microsoft Vulnerability Highlights
- Microsoft Release Summary
- Discover and Prioritize Vulnerabilities inVulnerability Management, Detection & Response (VMDR)
- Rapid Response with TruRisk Eliminate
- Qualys Monthly Webinar Series
Microsoft’s February 2026 Patch Tuesday focuses on closing security gaps that attackers could exploit, reinforcing the importance of timely patching in enterprise environments. Here’s a quick breakdown of what you need to know.
## Microsoft Patch Tuesday for February 2026
This month’s release addresses 61 vulner
Wiz
CVE-2026-21527 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 6.5
CVE-2026-21527 [MEDIUM] CVE-2026-21527 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-21527 :
Microsoft Exchange Server SE vulnerability analysis and mitigation
User interface (ui) misrepresentation of critical information in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
Source : NVD
## 6.5
Score
Published February 10, 2026
Severity MEDIUM
CNA Score 6.5
Affected Technologies
Microsoft Exchange Server SE
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 23.6
Exploitation Probability (EPSS) 0.1
Affected packages and libraries
cpe:2.3:a:microsoft:exchange_server:*:*:*:*:subscription:*:*:*
Sources
Windows Severity MEDIUM Has Fix Added at: Feb 12, 2026
Windows Severity MEDIUM Has Fix Added at: Feb 12, 2026
##
Sophos
February’s Patch Tuesday assumes battle stations
blogs_sophos
February’s Patch Tuesday assumes battle stations
Share This
Microsoft on Tuesday released 58 patches affecting 15 product families. Five of the addressed issues, all involving Azure, are considered by Microsoft to be of Critical severity, though only two require urgent attention (more on that below). Fifteen have a CVSS base score of 8.0 or higher, including two with a 9.8 base score. Six are known to be under active exploit in the wild, and three are publicly disclosed (including one not yet known to be under exploit).
At patch time, five CVEs are judged more likely to be exploited in the next 30 days by the company’s estimation, in addition to the six already detected to be so. Various of this month’s issues are amenable to direct detection by Sophos protections, and we include information on those in a table below. The release also
2026-02-10
Published