GHSA-ff77-26x5-69cr BIT-tomcat-2025-31651 CVE-2025-31651
Apache Tomcat Rewrite rule bypass
Critical
Maven
- Severity
- 0.0 / 10
- Critical · CVSS 4.0
- Exploit chance (EPSS)
- 4.26%
- Chance of exploitation in the next 30 days. Higher than 91.07% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-116 Improper Encoding or Escaping of Output
- CWE-150 Improper Neutralization of Escape, Meta, or Control Sequences
- Fix
- Available
- 2 packages have a fixed version
Description
Improper Neutralization of Escape, Meta, or Control Sequences vulnerability in Apache Tomcat. For a subset of unlikely rewrite rule configurations, it was possible for a specially crafted request to bypass some rewrite rules. If those rewrite rules effectively enforced security constraints, those constraints could be bypassed.
This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.5, from 10.1.0-M1 through 10.1.39, from 9.0.0.M1 through 9.0.102. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.0 though 8.5.100. Other, older, EOL versions may also be affected.
Users are recommended to upgrade to version 9.0.104, 10.1.40 or 11.0.6, which fix the issue.
Affected versions
Maven
| Package | Vulnerable | Fixed in |
|---|---|---|
| org.apache.tomcat.embed:tomcat-embed-core | >= 9.0.76, < 9.0.104 |
9.0.104 |
| org.apache.tomcat.embed:tomcat-embed-core | >= 10.1.10, < 10.1.40 |
10.1.40 |
| org.apache.tomcat.embed:tomcat-embed-core | >= 11.0.0-M2, < 11.0.6 |
11.0.6 |
| org.apache.tomcat.embed:tomcat-embed-core | >= 8.5.0, <= 8.5.100 |
No fix yet |
| org.apache.tomcat:tomcat-catalina | >= 9.0.76, < 9.0.104 |
9.0.104 |
| org.apache.tomcat:tomcat-catalina | >= 10.1.10, < 10.1.40 |
10.1.40 |
| org.apache.tomcat:tomcat-catalina | >= 11.0.0-M2, < 11.0.6 |
11.0.6 |
| org.apache.tomcat:tomcat-catalina | >= 8.5.0, <= 8.5.100 |
No fix yet |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
org.apache.tomcat.embed:tomcat-embed-core Maven → 9.0.104
- maven
<dependency><groupId>org.apache.tomcat.embed</groupId><artifactId>tomcat-embed-core</artifactId><version>9.0.104</version></dependency>- gradle
implementation("org.apache.tomcat.embed:tomcat-embed-core:9.0.104")
org.apache.tomcat:tomcat-catalina Maven → 9.0.104
- maven
<dependency><groupId>org.apache.tomcat</groupId><artifactId>tomcat-catalina</artifactId><version>9.0.104</version></dependency>- gradle
implementation("org.apache.tomcat:tomcat-catalina:9.0.104")
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- Low
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
- Exploit maturity
- Unreported
CVSS 3.1 9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-116: Improper Encoding or Escaping of Output
The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.
How to prevent it
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using the ESAPI Encoding control [REF-45] or a similar tool, library, or framework. These will help the programmer encode outputs in a manner less prone to error. Alternately, use built-in functions, but consider using wrappers in case those functions are discovered to have a vulnerability.
- Architecture and Design: If available, use structured mechanisms that automatically enforce the separation between data and code. These mechanisms may be able to provide the relevant quoting, encoding, and validation automatically, instead of relying on the developer to provide this capability at every point where output is generated. For example, stored procedures can enforce database query structure and reduce the likelihood of SQL injection.
- Architecture and Design, Implementation: Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages. Study all expected communication protocols and data representations to determine the required encoding strategies.
- Architecture and Design: In some cases, input validation may be an important strategy when output encoding is not a complete solution. For example, you may be providing the same output that will be processed by multiple consumers that use different encodings or representations. In other cases, you may be required to allow user-supplied input to contain control information, such as limited HTML tags that support formatting in a wiki or bulletin board. When this type of requirement must be met, use an extremely strict allowlist to limit which control sequences can be used. Verify that the resulting syntactic structure is what you expect. Use your normal encoding methods for the remainder of the input.
- Architecture and Design: Use input validation as a defense-in-depth measure to reduce the likelihood of output encoding errors (see CWE-20).
- Requirements: Fully specify which encodings are required by components that will be communicating with each other.
- Implementation: When exchanging data between components, ensure that both components are using the same character encoding. Ensure that the proper encoding is applied at each interface. Explicitly set the encoding you are using whenever the protocol allows you to do so.
CWE-150: Improper Neutralization of Escape, Meta, or Control Sequences
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as escape, meta, or control character sequences when they are sent to a downstream component.
How to prevent it
- Developers should anticipate that escape, meta and control characters/sequences will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- Implementation: While it is risky to use dynamically-generated query strings, code, or commands that mix control and data together, sometimes it may be unavoidable. Properly quote arguments and escape any special characters within those arguments. The most conservative approach is to escape or filter all characters that do not pass an extremely strict allowlist (such as everything that is not alphanumeric or white space). If some special characters are still needed, such as white space, wrap each argument in quotes after the escaping/filtering step. Be careful of argument injection (CWE-88).
- Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
- Implementation: When using output from an LLM, neutralize or strip escape codes before redirecting output to the terminal or other rendering engine that would process the codes. The neutralization could require that the character be printable and/or allowable whitespace, such as a carriage return or newline. Be deliberate about what to allow.
- Build and Compilation: When using an LLM: during tokenizer training, suppress escape codes from the tokenizer's vocabulary. Depending on context, this could be accomplished by removing the codes from input to the tokenizer, or removing the map from the string to its token ID. It is generally unlikely that this removal would adversely affect the quality or correctness of what is generated, e.g. advice requests for terminal settings to change colors.
References
Advisories
Packages
Other links
- github.com/apache/tomcat/commit/066bf6b6a15a4e7e0941d4acf096841165b97098
- github.com/apache/tomcat/commit/175dc75fc428930034a6c93fb52f830d955d8e64
- github.com/apache/tomcat/commit/ee3ab548e92345eca0cbd1f01649eb36c6f29454
- github.com/apache/tomcat/commit/fbecc915a10c5a3d634c5e2c6ced4ff479ce9953
- lists.apache.org/list.html
- lists.debian.org/debian-lts-announce/2025/07/msg00009.html
- tomcat.apache.org/security-10.html
- tomcat.apache.org/security-11.html
- tomcat.apache.org/security-9.html
- openwall.com/lists/oss-security/2025/04/28/3
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-83qj-6fr2-vhqg Apache Tomcat: Potential RCE and/or information disclosure and/or information corruption with partial PUT | Critical Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-qppj-fm5r-hxr3 HTTP/2 Stream Cancellation Attack | Medium Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-xjgh-84hx-56c5 Unrestricted Upload of File with Dangerous Type Apache Tomcat | High Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-cw54-59pw-4g8c Apache Tomcat Improper Access Control vulnerability | Critical Known exploited | Also affects org.apache.tomcat:tomcat-catalina |
| CVE-2020-1938 Improper Privilege Management in Tomcat | Critical Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-pjfr-qf3p-3q25 When running Apache Tomcat on Windows with HTTP PUTs enabled it was possible to upload a JSP file to the server | High Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-h3x4-894j-xpx5 Apache Tomcat's FORM authentication process has an Incorrect Authorization vulnerability | Critical | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-9xv2-5v5q-p794 Apache Tomcat's DIGEST authenticator has an Authentication Bypass by Capture-replay vulnerability | Critical | Also affects org.apache.tomcat.embed:tomcat-embed-core |
MergeHarbor checks every repository's dependencies against this database, ranks what matters by exploitability and reachability, routes it to the owning team and opens the fix pull request.
Check your repos with MergeHarbor