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USN-8931

Reporting by Ubuntu Security NoticesRead the original at ubuntu.com

Executive Summary

Apache HTTP Server has had several security-related findings reported concerning various functionalities, including WebDAV information exposure, FTP server response validation, and handling of HTTP requests and backend server responses. Specific vulnerabilities identified include the potential for remote attackers to obtain sensitive information via exposed WebDAV properties (CVE-2026-58415), potentially use an FTP response validation flaw to establish forward proxy connections to arbitrary hosts (CVE-2026-63045), and handle certain HTTP requests in ways that could lead to denial of service or arbitrary code execution (CVE-2026-63292). Further issues involve improper handling of backend server responses, which could lead to denial of service (CVE-2026-63686), and flaws related to Digest authentication requests that could allow authentication bypass (CVE-2026-73636) or improperly managed authentication requests leading to denial of service (CVE-2026-73637). An issue concerning HTTP response interpretation from backend servers allows for HTTP response smuggling attacks, affecting specific Ubuntu versions. Finally, flaws related to WebDAV requests could permit denial of service or data corruption for authenticated users (CVE-2026-93546). System updates are recommended to correct these issues.

Facts Only

* Apache HTTP Server exposed WebDAV property information, potentially allowing remote attackers to obtain sensitive information (CVE-2026-58415).
* Apache HTTP Server did not properly validate FTP server responses, which could allow a remote attacker to make a forward proxy connect to an arbitrary host (CVE-2026-63045).
* Apache HTTP Server incorrectly handled certain HTTP requests, potentially allowing a remote attacker to cause denial of service or execute arbitrary code (CVE-2026-63292).
* Apache HTTP Server did not properly handle certain responses from backend servers, which could lead to denial of service (CVE-2026-63686).
* Apache HTTP Server incorrectly interpreted HTTP responses from backend servers, potentially allowing HTTP response smuggling attacks, affecting Ubuntu 20.04 LTS, 22.04 LTS, 24.04 LTS, and 26.04 LTS (CVE-2026-63718).
* Apache HTTP Server did not properly validate Digest authentication requests, which a machine-in-the-middle attacker could use to bypass authentication (CVE-2026-73636).
* Apache HTTP Server did not properly manage authentication requests, which could lead to denial of service (CVE-2026-73637).
* Apache HTTP Server did not properly enforce access restrictions for user directories, potentially allowing a remote attacker to obtain sensitive information (CVE-2026-79768).
* Apache HTTP Server did not properly handle certain WebDAV requests, which could allow an authenticated user to cause denial of service or corrupt WebDAV property data (CVE-2026-93546).
* Updates are suggested to correct the problems.

Full Take

The aggregated findings point toward systemic weaknesses within the Apache HTTP Server's handling of various protocols and backend communications, suggesting an issue with maintaining strict boundary enforcement across different request types—file access (WebDAV), network traversal (FTP/proxy), and internal communication (backend responses). The pattern reveals a recurring theme where specific operational functions are insufficiently validated, opening pathways for information leakage or control flow manipulation. For instance, the combination of vulnerabilities like CVE-2026-58415 (information disclosure) and CVE-2026-63718 (response smuggling) suggests that flaws are not isolated to a single feature but exist at the intersection of protocol parsing and data handling. The existence of distinct, narrow vulnerabilities spanning different attack vectors (authentication bypass, DoS, arbitrary code execution) against the same core service indicates a challenge in comprehensive security policy implementation across diverse use cases. The imperative for system updates, while necessary, often addresses symptoms rather than the underlying architectural decision to implement these functions without rigorous cross-validation. This forces an examination of the foundational assumptions: if a server handles multiple, distinct operations, does it possess the necessary internal logic to guarantee isolation between them? What mechanisms should mandate consistent security validation across all operational layers, not just protocol adherence?

From the original · Ubuntu Security Notices

Packages - apache2 - Apache HTTP server Details 이지웅 discovered that Apache HTTP Server exposed WebDAV property information. A remote attacker could possibly use this issue to obtain sensitive information.

Read the full story at ubuntu.com

Sentinel — Human

Confidence

This text appears to be a highly structured compilation of security vulnerability discoveries and associated CVEs, suggesting it is either an automated report or a heavily condensed summary derived from human-sourced technical disclosures.

Signals Detected

Relatively direct listing style with clear demarcation of findings and CVEs; exhibits some fragmentation characteristic of compiled technical reports.

High density of factual citations (names, CVEs) presented sequentially without extensive connective prose, suggesting a compilation rather than narrative flow.

Perfect repetition of the structure '[Discoverer(s)] discovered that [Vulnerability]... (CVE-XXXXX)' points toward machine aggregation or highly structured manual compilation.

The content consists entirely of technical findings and reference numbers, which are highly verifiable artifacts. No subjective claims requiring deep contextual vetting were present.

Human Indicators

Inclusion of specific names (이지웅, Zhen Kong, Hyojae Lee, etc.) alongside technical findings suggests involvement in specific research communities or reporting channels.