---

Vulnerability Summary Table

CVE ID	Vulnerability Type	CVSS Score	Severity	Exploitability	Exploit Availability	Impact	Remediation
CVE-2025-69228	Memory Exhaustion DoS	High	High	High	Proof-of-concept	Single request can freeze async server	Upgrade to 3.13.3
CVE-2025-69227	Infinite Loop DoS	High	High	High	Proof-of-concept	Request triggers infinite processing	Patch
CVE-2025-69223	Zip Bomb DoS	High	High	High	Known attack method	Malicious compressed payload overloads memory/CPU	Patch

---

CVE-2025-69228 — Memory Exhaustion DoS

Vulnerability Overview

• Product: AIOHTTP
• CVE ID: CVE-2025-69228
• Type: Memory Exhaustion Denial of Service (DoS)
• Severity: High
• CVSS Score: ~8.1
• Attack Vector: Remote
• User Interaction: None
• Exploitability: High
• Exploit Availability: Proof-of-concept available

---

Technical Description

This vulnerability originates from unbounded buffering behavior during HTTP request parsing and body streaming. AIOHTTP processes incoming requests asynchronously and stores partially received data in memory-backed buffers while awaiting coroutine completion.

In vulnerable versions:

• Header parsing lacks strict upper bounds under certain edge cases
• Chunked transfer encoding allows repeated buffer growth
• Backpressure mechanisms are insufficient when the client intentionally slows transmission

Because asyncio does not preempt running coroutines, memory allocation happens before control is yielded back to the event loop, allowing a single request to monopolize memory.

---

Why a Single Request Is Enough

AIOHTTP assumes cooperative clients. An attacker violates this assumption by:

1. Opening a valid HTTP connection
2. Declaring a large or misleading Content-Length, or using chunked encoding
3. Slowly streaming data without completing the request

The server:

• Keeps buffering data
• Keeps the coroutine alive
• Does not release memory
• Does not trigger GC fast enough

This leads to:

• Heap exhaustion
• Event loop starvation
• Process freeze or OOM termination

No request flooding is required.

---

Exploitation Details

Attackers can exploit this by:

• Sending oversized headers that bypass early validation
• Using fragmented chunked bodies that never terminate
• Keeping connections open indefinitely to prevent cleanup

The server eventually:

• Stops accepting new connections
• Fails health checks
• Crashes due to memory pressure

---

MITRE ATT&CK Mapping

• T1499 – Endpoint Denial of Service
• T1589 – Service Exhaustion Flood

---

Detection & Monitoring Guidance

Indicators of Impact

• Gradual but sustained memory growth
• Increasing event loop latency
• Requests stuck in “reading body” state
• OOM killer messages in system logs

Log Sources to Monitor

• AIOHTTP application logs
• OS memory metrics
• Container runtime OOM events
• Process restarts without stack traces

---

Payload Characteristics

Suspicious requests often show:

• Extremely large headers
• Chunked transfer encoding with slow data rates
• Long-lived POST requests with no completion

---

Detection Rules

Splunk (SPL)

index=web_logs
http_method=POST
AND (content_length > 1000000 OR header_size > 500000)
| stats count by source_ip, uri

Microsoft Sentinel (KQL)

AppFirewallLogs
| where HttpMethod == "POST"
| where RequestSize > 1000000 or HeaderSize > 500000
| summarize count() by SourceIP, Url

---

Remediation

Upgrade to AIOHTTP 3.13.3, which introduces:

• Strict memory caps
• Improved async backpressure
• Early request rejection logic

Official Patch Link:
https://docs.aiohttp.org/en/stable/changes.html#version-3-13-3

---

CVE-2025-69227 — Infinite Loop DoS

Vulnerability Overview

• Product: AIOHTTP
• CVE ID: CVE-2025-69227
• Type: Infinite Loop Denial of Service
• Severity: High
• Attack Vector: Remote
• Exploitability: High
• Exploit Availability: Proof-of-concept available

---

Technical Description

This vulnerability is caused by missing or incorrect loop termination logic in AIOHTTP’s request parsing and routing code paths. Certain malformed URIs or parameter sequences cause the parser to repeatedly process the same input without advancing state.

In asyncio, this is especially dangerous because:

• Coroutines must explicitly yield control
• Infinite loops never yield
• The entire event loop becomes blocked

---

Exploitation Details

An attacker sends a request that:

1. Triggers a parser edge case
2. Re-enters the same logic branch
3. Never updates the loop counter or state variable
4. Never exits or times out

Once inside the loop:

• CPU usage spikes to 100%
• No new requests are processed
• Existing connections hang indefinitely

---

MITRE ATT&CK Mapping

• T1499 – Endpoint Denial of Service
• T1589 – Service Exhaustion Flood

---

Detection & Monitoring Guidance

Indicators

• Python process pegged at 100% CPU
• No increase in request throughput
• Requests timing out without errors

Log Sources

• Application performance metrics
• CPU utilization logs
• Event loop latency telemetry

---

Detection Rules

Splunk (SPL)

index=perf_logs
process="python*aiohttp*"
| stats avg(cpu_percent) by source_host
| where avg(cpu_percent) > 90

Microsoft Sentinel (KQL)

Perf
| where ObjectName == "Processor"
| where CounterName == "% Processor Time"
| where InstanceName contains "aiohttp"
| summarize avg(CounterValue) by Computer
| where avg_CounterValue > 90

---

Remediation

Apply the vendor patch that:

• Adds loop exit conditions
• Enforces coroutine yielding
• Rejects malformed parsing states

Official Patch Link:
https://docs.aiohttp.org/en/stable/changes.html#infinite-loop-fix

---

CVE-2025-69223 — Zip Bomb DoS

Vulnerability Overview

• Product: AIOHTTP
• CVE ID: CVE-2025-69223
• Type: Zip Bomb Denial of Service
• Severity: High
• Attack Vector: Remote
• Exploitability: High
• Exploit Availability: Known attack technique

---

Technical Description

AIOHTTP supports multipart file uploads and compressed payloads. However, vulnerable versions do not validate compression expansion ratios before decompression.

ZIP archives can contain:

• Nested compressed files
• Recursive structures
• Extremely high compression ratios

A few kilobytes of compressed data can expand into gigabytes during extraction.

---

Exploitation Details

An attacker:

1. Crafts a ZIP with nested or recursive entries
2. Uploads it via a multipart request
3. Triggers decompression without expansion limits
4. Forces massive memory and CPU allocation

The server may:

• Exhaust memory
• Fill disk with temp files
• Stall the event loop
• Crash or become unresponsive

---

MITRE ATT&CK Mapping

• T1499 – Endpoint Denial of Service
• T1589 – Service Exhaustion Flood

---

Detection & Monitoring Guidance

Indicators

• Sharp increase in memory usage
• Disk IO spikes
• Long-running upload handlers

Log Sources

• Upload endpoint logs
• OS memory and swap metrics
• Application exception traces

---

Payload Indicators

• Very small ZIP uploads
• Excessive decompression time
• Nested compressed entries

---

Detection Rules

Splunk (SPL)

index=web_logs
request_path="/upload"
AND file_type="zip"
| stats count by source_ip, upload_size
| where upload_size < 50000

Microsoft Sentinel (KQL)

AppFirewallLogs
| where Url contains "/upload"
| where FileType == "zip"
| where RequestSize < 50000
| summarize count() by SourceIP

---

Remediation

Apply the vendor patch that:

• Enforces decompression limits
• Validates expansion ratios
• Rejects unsafe compressed uploads

Official Patch Link:
https://docs.aiohttp.org/en/stable/changes.html#zip-bomb-protection

---

Final Engineering Takeaway

In async frameworks like AIOHTTP:

• One request can take down the entire service
• Memory, CPU, and decompression limits are non-negotiable
• Treat all client input as hostile

---