Apache: Security Vulnerabilities
XML External Entity (XXE) via Unsanitized Dictionary Parsing in Apache OpenNLP DictionaryEntryPersistor
Versions Affected: before 2.5.9, before 3.0.0-M3
Description: The DictionaryEntryPersistor class initializes a static SAXParserFactory at class-load time without enabling FEATURE_SECURE_PROCESSING or disabling DTD processing. When create(InputStream, EntryInserter) is invoked, the only feature set on the XMLReader is namespace support — external entity resolution and DOCTYPE declarations remain fully enabled. An attacker who can supply a crafted dictionary file (e.g., a stop-word list or domain dictionary) containing a malicious DOCTYPE declaration can trigger local file disclosure via file:// entity references or server-side request forgery via http:// entity references during SAX parsing, before the application processes a single dictionary entry. This is inconsistent with the project's own XmlUtil.createSaxParser() helper, which correctly sets FEATURE_SECURE_PROCESSING and disallow-doctype-decl and is used by all other XML parsing paths in the codebase. The public Dictionary(InputStream) constructor delegates directly to this method and is the documented API for loading user-supplied dictionaries, making untrusted input a realistic scenario.
Mitigation: 2.x users should upgrade to 2.5.9. 3.x users should upgrade to 3.0.0-M3. Users who cannot upgrade immediately should ensure that all dictionary files are sourced from trusted origins and should consider wrapping the Dictionary(InputStream) constructor with input validation that rejects any XML containing a DOCTYPE declaration before it reaches the parser.
CVSS Score
9.1
EPSS Score
0.005
Published
2026-05-04
Description:
Improper Control of Generation of Code ('Code Injection') vulnerability in Apache Atlas
Apache Atlas exposes a DSL search endpoint that accepts user-supplied query strings. Attacker can alter Gremlin traversal logic within grammar-allowed characters to access unintended data
Affect Version:
This issue affects Apache Atlas: from 0.8 through 2.4.0.
For the affect version >= 2.0, vulnerability is only when Atlas is deployed with below non-default configuration.
atlas.dsl.executor.traversal=false
Mitigation:
Users are recommended to upgrade to version 2.5.0, which fixes the issue.
CVSS Score
8.1
EPSS Score
0.005
Published
2026-05-04
A NULL pointer dereference in the mod_authn_socache in Apache HTTP Server 2.4.66 and earlier allows an unauthenticated remote user to crash a child process in a caching forward proxy configuration.
Users are recommended to upgrade to version 2.4.67, which fixes this issue.
CVSS Score
5.3
EPSS Score
0.005
Published
2026-05-04
HTTP response splitting vulnerability in multiple Apache HTTP Server modules with untrusted or compromised backend servers.
This issue affects Apache HTTP Server: from through 2.4.66.
Users are recommended to upgrade to version 2.4.67, which fixes the issue.
CVSS Score
6.5
EPSS Score
0.004
Published
2026-05-04
Double Free and possible RCE vulnerability in Apache HTTP Server with the HTTP/2 protocol.
This issue affects Apache HTTP Server: 2.4.66.
Users are recommended to upgrade to version 2.4.67, which fixes the issue.
CVSS Score
8.8
EPSS Score
0.497
Published
2026-05-04
A NULL pointer dereference in mod_dav_lock in Apache HTTP Server 2.4.66 and earlier may allow an attacker to crash the server with a malicious request.mod_dav_lock is not used internally by mod_dav or mod_dav_fs.
The only known use-case for mod_dav_lock was mod_dav_svn from Apache Subversion earlier than version 1.2.0.
Users are recommended to upgrade to version 2.4.66, which fixes this issue, or remove mod_dav_lock.
CVSS Score
7.5
EPSS Score
0.006
Published
2026-05-04
A timing attack against mod_auth_digest in Apache HTTP Server 2.4.66 allows a bypass of Digest authentication by a remote attacker.
Users are recommended to upgrade to version 2.4.67, which fixes this issue.
CVSS Score
4.8
EPSS Score
0.006
Published
2026-05-04
Out-of-bounds Read vulnerability in mod_proxy_ajp of
Apache HTTP Server.
This issue affects Apache HTTP Server: through 2.4.66.
Users are recommended to upgrade to version 2.4.67, which fixes the issue.
CVSS Score
5.3
EPSS Score
0.004
Published
2026-05-04
Improper Null Termination, Out-of-bounds Read vulnerability in Apache HTTP Server.
This issue affects Apache HTTP Server: through 2.4.66.
Users are recommended to upgrade to version 2.4.67, which fixes the issue.
CVSS Score
5.3
EPSS Score
0.005
Published
2026-05-04
An escalation of privilege bug in various modules in Apache HTTP 2.4.66 and earlier allows local .htaccess authors to read files with the privileges of the httpd user.
Users are recommended to upgrade to version 2.4.67, which fixes this issue.
CVSS Score
8.8
EPSS Score
0.007
Published
2026-05-04