CVE-2025-49763
Published: 19 June 2025
Summary
CVE-2025-49763 is a high-severity Uncontrolled Resource Consumption (CWE-400) vulnerability in Apache Traffic Server. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 11.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
The vulnerability is an uncontrolled resource consumption issue (CWE-400) in the ESI plugin of Apache Traffic Server. The plugin lacks any limit on maximum inclusion depth, so specially crafted ESI instructions can trigger unbounded memory consumption. It affects versions 10.0.0 through 10.0.5 and 9.0.0 through 9.2.10.
An unauthenticated remote attacker can send malicious ESI content over the network to exhaust server memory and produce a denial-of-service condition. The CVSS 7.5 score reflects network attack vector, low complexity, and high availability impact with no privileges or user interaction required.
The Apache project advisory recommends upgrading to 9.2.11 or 10.0.6. A new command-line option (--max-inclusion-depth) has been added to enforce a configurable limit on inclusion depth. The associated EPSS score remains low and flat at 0.0401 with no observed rise after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-18741
Vulnerability details
ESI plugin does not have the limit for maximum inclusion depth, and that allows excessive memory consumption if malicious instructions are inserted. Users can use a new setting for the plugin (--max-inclusion-depth) to limit it. This issue affects Apache Traffic…
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Server: from 10.0.0 through 10.0.5, from 9.0.0 through 9.2.10. Users are recommended to upgrade to version 9.2.11 or 10.0.6, which fixes the issue.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Limiting concurrent sessions directly prevents uncontrolled resource consumption by capping the number of active sessions per user or account.
Analysis identifies uncontrolled resource consumption indicative of denial-of-service or abuse attempts.
Contingency plan testing includes resource exhaustion scenarios to verify recovery, making it harder for attackers to sustain exploits that cause uncontrolled consumption.
Updated contingency plans include current procedures to detect, contain, and recover from resource exhaustion, limiting an attacker's ability to sustain impact from uncontrolled consumption.
Alternate site allows resumption of operations if resource exhaustion at the primary site is exploited to cause unavailability.
Alternate telecommunications services enable resumption of essential functions when primary services become unavailable due to uncontrolled resource consumption.
The team can analyze and respond to resource exhaustion incidents, reducing the impact of attacks that exploit uncontrolled consumption weaknesses.
Timely maintenance support and spare parts enable rapid recovery from failures induced by uncontrolled resource consumption, shortening the impact window of denial-of-service attacks.