CVE-2026-64943: Apache Answer Log Exposure Vulnerability

CVE-2026-64943 Overview

CVE-2026-64943 is an information disclosure vulnerability in Apache Answer, an open-source question-and-answer platform. Apache Answer versions through 2.0.2 write full API keys to application logs on every authenticated request. Any user with log-read access can recover active bearer credentials and replay them against the API. The flaw is classified under CWE-532: Insertion of Sensitive Information into Log File. The Apache Software Foundation addressed the issue in Apache Answer 2.0.3.

Critical Impact

Attackers with access to Apache Answer log files can harvest valid API bearer tokens and impersonate authenticated users, compromising confidentiality and integrity of the application.

Affected Products

• Apache Answer versions up to and including 2.0.2
• Deployments relying on default logging configurations
• Apache Answer 2.0.3 contains the fix

Discovery Timeline

• 2026-10-19 - CVE-2026-64943 published to NVD
• 2026-10-20 - Last updated in NVD database

Technical Details for CVE-2026-64943

Vulnerability Analysis

Apache Answer logs the full contents of inbound HTTP requests, including Authorization headers that carry API keys. Every authenticated API call writes the complete bearer credential into the application log stream. Operators, support staff, SIEM pipelines, log aggregators, and backup systems commonly retain these logs, which widens the credential exposure beyond the application host.

An attacker with read access to log files or log forwarding infrastructure can extract live API keys and reuse them to query the Answer API as the original user. Because the credentials are long-lived bearer tokens rather than single-use artifacts, replay is straightforward and does not trigger additional authentication challenges.

Root Cause

The root cause is the absence of redaction logic in Apache Answer's request logging path. Sensitive HTTP header fields are serialized verbatim instead of being masked, hashed, or omitted. This maps directly to [CWE-532], where sensitive information is inserted into logs that have broader access scope than the originating data.

Attack Vector

Exploitation requires network access to the API with low privileges to generate authenticated traffic, combined with read access to the server logs. See the Apache Mailing List Thread and the OpenWall OSS Security Update for the upstream advisory. No public proof-of-concept exploit has been published. The EPSS probability stands at 0.396% as of 2026-10-22.

No verified exploit code is available. The vulnerability is best understood as an insecure logging pattern rather than a parsing or memory issue; see the upstream advisory for details.

Detection Methods for CVE-2026-64943

Indicators of Compromise

• Presence of Authorization: Bearer strings or raw API key values inside Apache Answer application log files.
• Repeated API requests from a single source using credentials belonging to multiple distinct user accounts.
• Access to log directories or log aggregation indices from accounts that do not normally require log visibility.

Detection Strategies

• Grep historical and current Apache Answer logs for authorization header patterns and token-like strings to confirm exposure scope.
• Correlate API request source IP addresses with user accounts to flag credential replay from unexpected locations.
• Audit log pipeline destinations, including SIEM, object storage, and backup snapshots, for cached copies of unredacted credentials.

Monitoring Recommendations

• Alert on reads of Apache Answer log paths by non-administrative users and processes.
• Monitor API usage for sudden shifts in client user-agent, geolocation, or request volume per API key.
• Track configuration changes to the Apache Answer logger to confirm redaction remains in place after upgrades.

How to Mitigate CVE-2026-64943

Immediate Actions Required

• Upgrade Apache Answer to version 2.0.3, which removes credentials from log output.
• Rotate all API keys and bearer tokens issued by affected Apache Answer deployments, since prior tokens must be considered exposed.
• Purge or restrict access to historical log files, backups, and SIEM indices that may contain captured credentials.
• Restrict log-read permissions to a minimal set of operational accounts.

Patch Information

The Apache Software Foundation released Apache Answer 2.0.3 to resolve CVE-2026-64943. Administrators should follow the upgrade instructions referenced in the Apache Mailing List Thread and validate that logs no longer contain Authorization header values after the upgrade.

Workarounds

• Place a reverse proxy or logging middleware in front of Apache Answer that strips or masks Authorization headers before persistence.
• Lower the application log verbosity to exclude request headers until the upgrade is applied.
• Enforce short API key lifetimes and rotation to reduce the window of replay for any leaked credentials.

# Example reverse proxy redaction (NGINX) applied in front of Apache Answer
# Removes Authorization headers from access log output
log_format answer_safe '$remote_addr - $remote_user [$time_local] '
                      '"$request" $status $body_bytes_sent '
                      '"$http_referer" "$http_user_agent"';

server {
    listen 443 ssl;
    server_name answer.example.com;

    access_log /var/log/nginx/answer_access.log answer_safe;

    location / {
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_pass http://127.0.0.1:9080;
    }
}