Skip to main content

SolarWinds Serv-U EUVDEUVD-2026-46295

| CVE-2026-28315 MEDIUM
Cross-site Scripting (XSS) (CWE-79)
2026-07-21 SolarWinds GHSA-27f7-w76r-h7r2
6.2
CVSS 3.1 · Vendor: SolarWinds
View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Authenticate as high-privilege admin
  2. Delivery
    Inject stored XSS payload into Serv-U interface field
  3. Exploit
    Victim admin browses to poisoned view
  4. Execution
    Browser executes malicious script
  5. Persist
    Session token exfiltrated to attacker
  6. Impact
    Attacker hijacks victim admin session

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK

2 techniques across 2 tactics: Initial Access, Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

The attacker must already hold a high-privilege administrator account on the SolarWinds Serv-U instance (PR:H per the CVSS vector) sufficient to write data into the field containing the stored XSS payload. A second administrator must then actively browse to the affected interface element (UI:R), triggering script execution in their browser. Exploitation is therefore limited to insider-threat scenarios, compromised admin credential chains, or environments where multiple admin accounts exist with differing trust levels. Default-configuration deployments are not exploitable by unauthenticated or low-privilege external attackers. The scope is limited to confidentiality (C:H) with no integrity or availability impact - the attacker gains session-level access, not the ability to modify server data or cause downtime directly.

Impact

The CVSS base score of 6.2 reflects a meaningful but bounded risk profile. The vector AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:N/A:N confirms network delivery with no complexity barrier, but critically requires the attacker to hold high administrative privileges to plant the payload, and a separate administrator must then interact with the poisoned interface element. This significantly constrains the realistic attacker population - the most plausible threat actor is a lower-trust admin or compromised admin account escalating impact against a higher-trust peer, or an insider threat. No EPSS data was provided in the input; no KEV listing is present, meaning active exploitation is not confirmed by CISA. No public proof-of-concept has been identified at time of analysis. Despite the High confidentiality rating, the I:N and A:N components mean the vulnerability cannot directly modify data or cause downtime - its value to an attacker is credential or session pivot, not immediate destructive capability. Priority should be moderate: patch promptly but it does not displace actively-exploited critical vulnerabilities in triaging.

Exploit ScenarioDerived

An attacker who has compromised or legitimately holds a high-privilege Serv-U administrator account injects a JavaScript payload into a field that is stored by the application and rendered in the administrative interface - for example, a filename, user comment, or configuration label. When a peer administrator subsequently navigates to the affected view, their browser executes the script, which reads the administrator's session cookie and exfiltrates it to an attacker-controlled endpoint. The attacker replays the stolen session token to fully impersonate the victim administrator without needing their credentials. No public proof-of-concept has been identified at time of analysis.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.3% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv1 – Jul 21, 2026

Stored cross-site scripting in SolarWinds Serv-U enables session hijacking and information disclosure from administrator accounts via malicious script persistence in the application. The vulnerability requires a high-privileged attacker to inject the payload, which then executes in the browser context of any administrator who views the poisoned content - a classic privilege-boundary-crossing XSS pattern confirmed by the CVSS scope-change flag. No public exploit code has been identified at time of analysis, and a vendor fix appears in Serv-U 2026.3 based on release note references.

RemediationAI

The primary fix is to upgrade SolarWinds Serv-U to version 2026.3, as indicated by the release notes reference at https://documentation.solarwinds.com/en/success_center/servu/content/release_notes/servu_2026-3_release_notes.htm. Consult the vendor advisory at https://www.solarwinds.com/trust-center/security-advisories/CVE-2026-28315 for official guidance and any additional mitigations. Where immediate patching is not possible, restrict administrative web interface access to trusted internal networks or dedicated management VLANs, reducing the attack surface for payload injection. Additionally, enforcing strict role separation so that only a minimal number of accounts hold administrative write access limits which principals can inject a stored payload. Enabling Content Security Policy headers at a reverse proxy layer may partially reduce script execution impact, but should not be treated as a substitute for patching given the application controls the relevant output context.

Affected VersionsENISA

Serv-U 15.5.4 HF1 and below

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

SolarWinds Serv-U is a managed file transfer and FTP/SFTP server platform widely deployed in enterprises for secure file sharing and transfer workflows. The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), the canonical stored XSS root cause, meaning user-supplied input is persisted to a data store and later rendered without adequate output encoding in an administrative web interface. The CPE string cpe:2.3:a:solarwinds:serv-u:*:*:*:*:*:*:*:* covers all versions of the application tier without a fixed upper bound recorded in NVD at time of analysis. The CVSS scope-change (S:C) reflects that the injected script executes in the victim administrator's browser security context rather than the server's own execution context, enabling cross-origin session token theft.

Know when Serv U gets its next vulnerability

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources

No credit card · 7-day full trial

Severity by source

Vendor (SolarWinds) PRIMARY 6.2 MEDIUM
AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:N/A:N
vuln.today AI 6.2 MEDIUM

High privileges required to plant payload; scope changes because script executes in victim's browser; no integrity or availability impact applies.

3.1 AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:N/A:N
4.0 AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N

Primary rating from Vendor (SolarWinds).

CVSS VectorVendor: SolarWinds

Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
Required
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

DescriptionCVE.org

SolarWinds Serv-U was found to be affected by a stored cross-site scripting vulnerability that could lead to session hijacking or information disclosure from an administrator account.

Threat Intelligence Overview

EPSS Score
0.3%
Top 80% exploitable
Prevalence
Medium
enterprise MFT/FTP server, widely used but not ubiquitous
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.3%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

31
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +31
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

More in Serv U

View all
CVE-2026-28318 HIGH POC
7.5 Jun 04

Remote denial-of-service in SolarWinds Serv-U allows unauthenticated attackers to crash the Serv-U service by sending sp

CVE-2021-35211 CRITICAL POC
10.0 Jul 14

Microsoft discovered a remote code execution (RCE) vulnerability in the SolarWinds Serv-U product utilizing a Remote Mem

CVE-2024-28995 HIGH POC
7.5 Jun 06

SolarWinds Serv-U was susceptible to a directory transversal vulnerability that would allow access to read sensitive fil

CVE-2021-25276 HIGH POC
7.1 Feb 03

In SolarWinds Serv-U before 15.2.2 Hotfix 1, there is a directory containing user profile files (that include users' pas

CVE-2018-25252 MEDIUM POC
6.9 Apr 04

FTP Voyager 16.2.0 contains a denial of service vulnerability that allows local attackers to crash the application by in

CVE-2018-10241 MEDIUM POC
6.5 May 16

A denial of service vulnerability in SolarWinds Serv-U before 15.1.6 HFv1 allows an authenticated user to crash the appl

CVE-2021-32604 MEDIUM POC
5.4 May 11

Share/IncomingWizard.htm in SolarWinds Serv-U before 15.2.3 mishandles the user-supplied SenderEmail parameter, aka "Sha

CVE-2026-28316 CRITICAL
9.1 Jul 21

Privilege escalation in SolarWinds Serv-U allows an authenticated domain administrator account to abuse an insecure dire

CVE-2026-28308 CRITICAL
9.1 Jul 21

Privilege-scoped remote code execution in SolarWinds Serv-U managed file transfer server stems from an insecure direct o

CVE-2026-28305 CRITICAL
9.1 Jul 21

Privilege-to-root remote code execution in SolarWinds Serv-U managed file transfer server stems from an insecure direct

CVE-2026-28304 CRITICAL
9.1 Jul 21

Remote code execution in SolarWinds Serv-U managed file transfer/FTP server allows an attacker to run arbitrary code rem

CVE-2026-28302 CRITICAL
9.1 Jul 21

Privilege escalation to remote code execution as root in SolarWinds Serv-U stems from an insecure direct object referenc

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy