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HTTP/2: memory exhaustion due to CONTINUATION frame flood

High
phlax published GHSA-gghf-vfxp-799r Apr 4, 2024

Package

No package listed

Affected versions

1.29.0, 1.29.1

Patched versions

1.29.2

Description

Summary

Envoy HTTP/2 protocol stack is vulnerable to memory exhaustion due to flood of CONTINUATION frames.

Affected Components

HTTP/2 protocol stack.

Details

Envoy's HTTP/2 codec does not reset a request when header map limits have been exceeded. This allows an attacker to send an sequence of CONTINUATION frames without the END_HEADERS bit set causing unlimited memory consumption.

Impact

Denial of service through memory exhaustion.

Attack vector(s)

Sequence of CONTINUATION frames without the END_HEADERS bit set, from an untrusted HTTP/2 peer.

Patches

Users should upgrade to versions 1.29.2 to mitigate the effects of the CONTINUATION flood.
Note that this vulnerability is a regression in Envoy version 1.29.0 and 1.29.1 only.

Workarounds

Downgrade to version 1.28.1 or earlier or disable HTTP/2 protocol.

Detection

Abnormal process termination due to memory exhaustion. Memory profiles showing high memory consumption in HTTP/2 codec.

Credits

Bartek Nowotarski https://nowotarski.info/

Severity

High

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
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVE ID

CVE-2024-27919

Weaknesses