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Buffer not correctly recycled in Gzip Request inflation

Moderate severity GitHub Reviewed Published Nov 28, 2020 in jetty/jetty.project • Updated Feb 21, 2024

Package

maven org.eclipse.jetty:jetty-server (Maven)

Affected versions

>= 9.4.0, <= 9.4.34

Patched versions

9.4.35.v20201120

Description

Impact

If GZIP request body inflation is enabled and requests from different clients are multiplexed onto a single connection and if an
attacker can send a request with a body that is received entirely by not consumed by the application, then a subsequent request
on the same connection will see that body prepended to it's body.

The attacker will not see any data, but may inject data into the body of the subsequent request

CVE score is 4.8 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L

Workarounds

The problem can be worked around by either:

  • Disabling compressed request body inflation by GzipHandler.
  • By always fully consuming the request content before sending a response.
  • By adding a Connection: close to any response where the servlet does not fully consume request content.

References

@waynebeaton waynebeaton published to jetty/jetty.project Nov 28, 2020
Published by the National Vulnerability Database Nov 28, 2020
Reviewed Dec 2, 2020
Published to the GitHub Advisory Database Dec 2, 2020
Last updated Feb 21, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L

EPSS score

1.327%
(86th percentile)

Weaknesses

CVE ID

CVE-2020-27218

GHSA ID

GHSA-86wm-rrjm-8wh8

Source code

Credits

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