Sensitive Data Exposure via Logs in Splunk TcpChannel
CVE-2026-20239 is a high-severity information disclosure vulnerability affecting Splunk Enterprise versions below 10.2.2 and 10.0.5, and Splunk Cloud Platform versions below 10.3.2512.8, 10.2.2510.11, 10.1.2507.21, and 10.0.2503.13. The issue is in Splunk’s TcpChannel component, where a logic flaw and improper output sanitization cause the platform to log full, unparsed I/O buffer contents at WARN level when socket errors occur and active communication data is discarded. These raw buffers are written into the _internal index, where they may contain sensitive material including active session cookies and cleartext HTTP response bodies.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
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Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
7 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A sensitive data exposure vulnerability in Splunk Enterprise and Splunk Cloud Platform caused by improper output sanitization in TcpChannel, allowing retrieval of sensitive information from logs.
A logic vulnerability in Splunk Enterprise's TcpChannel component that can expose sensitive data, including session cookies and cleartext HTTP response bodies, through unsanitized raw I/O buffer contents written to internal logs.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.