VDB-95120 · CVE-2016-6581 · BID 92315

Python HPACK Library up to 2.2.0 HTTP/2 HPACK Bomb resource management

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.4$0-$5k0.00

Summaryinfo

A vulnerability was found in Python HPACK Library up to 2.2.0 and classified as problematic. This vulnerability affects unknown code of the component HTTP/2. Such manipulation leads to resource management (HPACK Bomb). This vulnerability is referenced as CVE-2016-6581. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in Python HPACK Library up to 2.2.0 (Software Library). It has been rated as problematic. Affected by this issue is an unknown code of the component HTTP/2. The manipulation with an unknown input leads to a resource management vulnerability (HPACK Bomb). Using CWE to declare the problem leads to CWE-399. Impacted is availability. CVE summarizes:

A HTTP/2 implementation built using any version of the Python HPACK library between v1.0.0 and v2.2.0 could be targetted for a denial of service attack, specifically a so-called "HPACK Bomb" attack. This attack occurs when an attacker inserts a header field that is exactly the size of the HPACK dynamic header table into the dynamic header table. The attacker can then send a header block that is simply repeated requests to expand that field in the dynamic table. This can lead to a gigantic compression ratio of 4,096 or better, meaning that 16kB of data can decompress to 64MB of data on the target machine.

The bug was discovered 08/04/2016. The weakness was published 01/10/2017 (Website). The advisory is shared for download at securityfocus.com. This vulnerability is handled as CVE-2016-6581 since 08/03/2016. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available.

The vulnerability was handled as a non-public zero-day exploit for at least 159 days. During that time the estimated underground price was around $0-$5k.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at SecurityFocus (BID 92315†). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.4

VulDB Base Score: 5.3
VulDB Temp Score: 5.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Name: HPACK Bomb
Class: Resource management / HPACK Bomb
CWE: CWE-399 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Timelineinfo

08/03/2016 🔍
08/04/2016 +1 days 🔍
08/04/2016 +0 days 🔍
01/10/2017 +159 days 🔍
01/10/2017 +0 days 🔍
01/11/2017 +1 days 🔍
04/20/2025 +3021 days 🔍

Sourcesinfo

Advisory: securityfocus.com⛔
Status: Not defined
Confirmation: 🔍

CVE: CVE-2016-6581 (🔍)
GCVE (CVE): GCVE-0-2016-6581
GCVE (VulDB): GCVE-100-95120
SecurityFocus: 92315 - Python HPACK CVE-2016-6581 Remote Denial of Service Vulnerability
OSVDB: - CVE-2016-6581 - Python HPACK - HPACK Bomb Issue

Entryinfo

Created: 01/11/2017 09:36
Updated: 04/20/2025 14:23
Changes: 01/11/2017 09:36 (57), 07/18/2020 17:05 (7), 04/20/2025 14:23 (17)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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