CVE-2024-27919

HTTP/2: memory exhaustion due to CONTINUATION frame flood

HIGH
7.5
CVSS Score
Published: April 4, 2024 at 02:30 PM UTC
Updated: June 17, 2026 at 07:20 AM UTC
1 product affected across 1 vendorEnvoy

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Severity
HIGH7.5
Exploit prediction
EPSS 87%
SSVC
No known exploit

Description

Envoy is a cloud-native, open-source edge and service proxy. In versions 1.29.0 and 1.29.1, theEnvoy HTTP/2 protocol stack is vulnerable to the flood of CONTINUATION frames. 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. This can lead to denial of service through memory exhaustion. 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. As a workaround, downgrade to version 1.28.1 or earlier or disable HTTP/2 protocol for downstream connections.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.29.21.29.0 ≤ v < 1.29.21.29.01.29.1
Affected range stops below 1.29.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-390

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