CVE-2026-28318
SolarWinds Serv-U is susceptible to specially crafted POST requests that crash the Serv-U service without authentication using Content-Encoding: deflate.
High
Known exploited
- Severity
- 7.5 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 43.65%
- Chance of exploitation in the next 30 days. Higher than 98.74% of scored vulnerabilities.
- Known exploited
- Yes
- In CISA's catalog since Jun 5, 2026
- Weakness
- CWE-400 Uncontrolled Resource Consumption
- Fix
- None yet
- No fixed version published
Exploited in the wild. SolarWinds Serv-U Uncontrolled Resource Consumption Vulnerability (SolarWinds Serv-U). Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Due for U.S. federal agencies by Jun 19, 2026.
Description
SolarWinds Serv-U is susceptible to specially crafted POST requests that crash the Serv-U service without authentication using Content-Encoding: deflate. Mitigation steps are provided to secure customer environments in the SolarWinds Trust Center if you are unable to deploy the update
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
Severity breakdown
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-400: Uncontrolled Resource Consumption
The product does not properly control the allocation and maintenance of a limited resource.
How to prevent it
- Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
- Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
- Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
- Implementation: Ensure that all failures in resource allocation place the system into a safe posture.
References
Advisories
Other links
Timeline
- Published
- Added to CISA's Known Exploited Vulnerabilities catalog
- Remediation due for U.S. federal agencies
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-cggf-277g-3q54 pypdf has possible large memory usage when parsing page tree | High | Same weakness, CWE-400 |
| GHSA-3g3m-2fjr-6pw4 Glob: AbortSignal cancellation bypass allows post-timeout filesystem traversal | Medium | Same weakness, CWE-400 |
| GHSA-42gh-23hr-vphw pypdf has possible long runtimes when retrieving page labels | High | Same weakness, CWE-400 |
| GHSA-4vqv-7265-gm2w pypdf has possible large memory usage for exceptions in strict mode | High | Same weakness, CWE-400 |
| GHSA-62m5-6wh8-28x7 pypdf has possible long runtimes/large memory usage for encrypted PDF files | High | Same weakness, CWE-400 |
| GHSA-7wch-p9px-956x Forge: Regular expression denial of service in PEM decoding (pem.decode) | High | Same weakness, CWE-400 |
| GHSA-fw5c-8223-6h42 russh: peer-declared zero maximum packet size permanently stalls channel writes (silent AsyncWrite hang) | Medium | Same weakness, CWE-400 |
| GHSA-x3rh-gjgm-fmqc pypdf has possible large memory usage when parsing cross-reference streams | High | Same weakness, CWE-400 |
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