CVE-2025-31699

HIGH CVSS 8.9 PoC Available
Published: 2026-10-21
Modified: 2026-10-23
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AI Threat Summary

CVE-2025-31699 is a high-severity vulnerability with a CVSS score of 8.9 affecting the target software. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.

Description

Apache Traffic Server can return an origin connection to the shared pool while the origin is still waiting on a request body the client declared but never fully sent, including when the client used Expect: 100-continue. The origin then reads a later request on that connection as leftover body data, which lets an attacker smuggle requests past ATS access controls, disrupt other users' requests, or poison the cache. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.15, from 10.0.0 through 10.1.4, 10.2.0. Users are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue.

Attack Chain
1
Reconnaissance

Attacker scans for vulnerable versions using version banners or PoC scanners

2
Initial Access

Attacker triggers CVE-2025-31699 vulnerability with a crafted request or payload

3
Execution

Vulnerability exploited to perform unauthorized actions on the target system

4
Impact

Depending on vulnerability type, attacker achieves data access, service disruption, or code execution

MITRE ATT&CK Techniques
T1190 Exploit Public-Facing Application
Initial Access

Public-facing application vulnerability exploited for initial access

T1203 Exploitation for Client Execution
Execution

Vulnerability exploited to execute attacker-controlled code

Indicators of Compromise
Type Value Description
user_agent Mozilla/5.0 (compatible; exploit/1.0) Generic exploit scanner user agent pattern
url /api/vuln-endpoint?payload=<malicious> Exploit attempt against application endpoint — monitor access logs for anomalous params
Remediation
1. Apply vendor-supplied security patches immediately. 2. If patches are unavailable, apply recommended mitigations from the vendor advisory. 3. Enable WAF rules or IDS signatures to detect exploitation attempts. 4. Monitor logs for indicators of compromise listed above. 5. Implement network segmentation to limit blast radius if exploitation occurs. 6. Subscribe to vendor security advisories for this product.
Quick Facts
CVE ID CVE-2025-31699
CVSS Score 8.9
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L
Published 2026-10-21
Exploited No
CISA KEV No
PoC Available
References
External Resources
NVD Entry BleepingComputer The Hacker News